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FAQs about Ultraviolet Sterilizer Rationale/Use

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Not absolutely effective for preventing or curing pathogenic disease... though do improve water quality, lower overall free-living/water-borne microbial levels, reduce algal growth, increase ORP, DO.

UV Sterilizer; Use    9/9/14
I have a UV sterilizer question that you may be able to help with. I have a 200 gal aquarium with two bulkheads on opposite sides of the tank (a reef ready setup). I have a quiet one 2200 and a Eheim compact 5000 pump that I leave pumping at full blast. I have the quiet one pump going through a turbotwist 12x 36 watt. However, I know that this is not enough to help with parasite control for a tank of my size.
<Does help...>
I ordered an emperor HO 80 watt, but this is a beast of a UV sterilizer, and will not fit underneath my tank with my current setup. My question is this, if I combined two UV sterilizers, would that be adequate for the additional flow?
<Likely so>
Does it increase the effectiveness for protozoa?
<Mmm; there is an optimum flow-rate per unit...>
For example, if I combined two 36 watt turbotwists, would that make a difference with approximately 600 gph of water flowing through them back to back? I hope that this makes sense.
Thank you much,
<Doing all one can... to avoid pathogenic disease... by selecting best species, specimens, isolating them; perhaps running them through
prophylactic baths... Optimizing water quality, nutrition... are all important.
Have you read here: http://wetwebmedia.com/mardisease.htm
Bob Fenner>


I'm wondering about using either an ozone generator or a UV system to help me keep on top of potential disease.  Which would you use and what are the benefits of either.  If I get an ozone generator do I need a controller for it?  Please help it's all so confusing.  Thanks.

James Wilson, Bath 

This will have to be a greatly foreshortened explanation to what could be a very long explanation James. Both types of water filtration gear will indirectly help w/ reducing the pathogenicity of disease causing organisms'¦ through improvement in water quality. 'Some' well-engineered ultraviolet sterilizers that are fitted with proper flow rates are able to 'zap' small organisms (bacteria, fungi, perhaps some Protozoans) sufficiently to kill them outright; all do some good in producing ozone (O3) to a degree. There are Ozonizers (ozone generators) that are actually ultraviolet lamps, though most in our interest are corona discharge types.

            Ozone generation by itself is a great sanitizer of water, increasing dissolved oxygen, increasing RedOx, helping to resist acidification and all its related downsides (unavailability of alkalinity, alkaline earth materials'¦ i.e. Calcium, Magnesium, Strontium'¦). This technology is such a boon that there are NO commercial aquariums, marine livestock wholesalers, or aquaculture facilities of size that I've been to that don't employ it. In fact, given the choice of UV or Ozone, not only would I take the latter, but the next choice would be a desiccator (to dry out the air going into the Ozonizer) than a UV in turn.

            Rest assured, you are not alone in your confusion. The variation in the utility of this gear, its appropriate application, and attendant possible beneficial effects are subject to a myriad of interpretation. Both will help in a few ways, but Ozone is my greatly preferred (over UV) adjunct to an otherwise well-filtered system.

            A controller for the Ozonizer is not really necessary'¦ IF the unit is sized about where you want it and 'oxidizable materials' are about constant (not hard to do). Even small (hundreds of milligrams of O3) ozonizers have adjustable dials for output'¦ with simple measure; one can get close to what the constant output should be.

UV sterilizer use with Ozone Generator - Sure, just realize that they do two different things. 7/26/2010
<Hi Jeff.>
I've been searching the internet for the last couple hours trying to find an answer to my question with no avail. I do believe I've found the answer before, but I don't remember.
Anyway, I started using an Ozone Generator a few months ago. It's made by Supreme Aqua. I noticed a few weeks ago that the JG fitting on my AquaC EV-180 Skimmer had disintegrated .
<Not uncommon with ozone, it is a very strong oxidizer, and can destroy most plastics within a very short period of time. You really want fittings made out of a material called "Kynar" as it is ozone resistant>
I talked to Steve with AquaC and he promptly sent me out two replacement fittings. However, after cleaning off the skimmer, I saw the body of the skimmer was cracked across the spot where the JG fitting screws in and all
the way across the body and down the side. It was not cracked all the way through, however it looked like it might not be far from splitting in half.
<Hmm... may be a function of the JG fitting being tightened too much rather than ozone.>
I was greatly alarmed. I contacted Jason at AquaC and he gave me his cell number and sent me a replacement skimmer. Great Customer Service!
<Aqua-C is known for their excellent customer service. I'm pleased to say I'm not in the least surprised that you got such an excellent response.>
After hooking up the new skimmer, I decided not to take a chance with my current ORP controller and Ozonizer .
I ordered a Ozotech Poseidon along with a Neptune Apex controller.
<Good brands, but I don't see the point, obviously the one you had was producing ozone very well. The JG fitting failed because it was exposed to ozone, not because your ozone generator was an off brand.>
My current controller is off brand and was shipped from overseas.
<Most of them are made and shipped from overseas.>
I'm not sure it's the culprit , but I don't see anyone else using that brand or the off brand ozone generator so I'm not taking any more chances with cheap equipment.
<I use an Enley ozone generator I picked up on EBay over a year ago for less than $100 USD. Still going strong running 24 hours a day.>
My question is do I need to run my UV sterilizer along with the Ozone generator or is it redundant.
<They do two different things really. Ozone is used to burn off additional organic compounds in the water. UV is used to kill off bacteria, viruses, and the like. UV lamps DO produce ozone, but in a very small amount.>
Thank you,
<My pleasure.>

Ick, UV and QT, 7/6/10
Hi Team,
We have a Valentini puffer in a quarantine tank at present, who is showing signs of Ick. She is currently sharing the qt with two Chromis (no signs at present).
<But probably still infected.>
I've read a lot of discussion on Ick which says "a bare bottom tank for qt is only half the solution", and others which say "UV in a display tank is only half the solution".
Could they work well together as a whole solution - i.e.. a bare bottomed tank with good circulation, which passes its water through a UV to kill the cysts when they drop?
<A UV will not effect a cure, and a bare bottom tank alone does nothing but provide a suitable tank for chemotherapy.>
What are your thoughts? Do you think the UV will kill the cysts, as opposed to just the free-swimming parasites?
<Will not kill either reliably.>
(pH, ammonia, nitrite, nitrate all good in qt. Salinity is normal; I am hesitant to drop the salinity as I have read conflicting information on how this does/doesn't stress the fish over extended periods.)
<I would investigate one of the Quinine drugs for use with a puffer.
http://www.wetwebmedia.com/quinmedfaqs.htm .>
Best regards,

UV Sterilization, lg. sys... filtr.  6/24/10
Hey Crew
I have a 500 gallon reef tank and have had one for some time now, about 5 years. I've had my share of ups and downs, more downs than ups, though.
I've had corals that require "expert care" that thrive and corals that are considered "easy" and die. The same goes with fish. I do nothing special.
I don't have any high tech controllers, or quarantine tanks. All I do is weekly water changes, about 20-30 gallons and have a skimmer and a red sea ozonizer.
The ozonizer I hardly use because I'm about half scared to use it.
<Don't be. These devices are not harmful. See the area linked below to assuage your fears>
The ORP reads between 250-300. By the way what is the therapeutic level for the ORP and dosage rate for the ozone?
<... please read here:
or the article vers. linked above>
The nitrates are always low and there is a trace amount of phosphate. I seem to be having an ich problem with my blue tangs and I recently lost a Sailfin tang to what I think was dropsy.
<A symptom, w/ a few possible etiologies... again, please search/read on
WWM as we request before writing us>
I've lost alot
<... no such word>
more than this, but I think ich is the problem which leads to secondary infections.
<Ahh! You may well be correct here Lar>
My male lyretail Anthias is now getting a cloudy eye without visible signs of parasites. I need to know about the UV
<Your Ozonizer is doing about all the good that a UV would>
such as...a good idea...which one to get and what size for a 500 gallon tank.
<See WWM re... the Vectron line by TMC is my fave for this size system... and others. Bob Fenner>
Thanks for your time and help

Will a UV Sterilizer control algae? 5/6/10
Hi crew!
Will a UV Sterilizer control algae?
<A U-V steriliser will reduce, perhaps eliminate, floating algae types such as those that make water green. It will have no impact at all on blanketweed and other types of attached algae. Cheers, Neale.>
Re: Will a UV Sterilizer control algae?
I've got a 240 gallon freshwater tank that I'm still scrubbing brown algae off of the glass every week. Would this help?
Is the brown algae free floating before it attaches to the glass?
Algae is a problem in unbalanced aquaria; better lights, more fast-growing plants, tends to improve things. Cheers, Neale.>

UV On A Reef Tank? -- 04/12/10
Can you use a UV light on a reef tank?
<<As in an Ultraviolet Sterilizer unit, yes you can (read here and among the associated links: http://www.wetwebmedia.com/UVFAQs.htm ), though I consider these units to be too cumbersome re their maintenance (the sleeves need to be kept 'spotless'), and maybe even detrimental on a reef tank due to some loss of microscopic planktonic life>>
Would it be better or worse?
<<In reality'¦it's likely of small consequence either way. EricR>>

Using a U.V. Sterilizer during cycling a tank   2/6/10
Hey Bob, I have a quick question for you. Does using a UV sterilizer during a tank cycle ( fish only with no live rock or freshwater tank) slow down or inhibit the cycling process? Thanks and I hope to hear from you soon.
<I think this would be an interesting (scientific) experiment to conduct.
Celebratedly, the bacteria involved in Nitrification reside on hard surfaces... not in the water column where they'd be readily exposed to the UV over time... but the UV does much more than "zap" such life... among other notable effects such irradiation raises RedOx and DO... maybe reducing the populations of water-suspended microbial life
enhances/decreases establishment... I suspect that having, running a UV might well shorten the time of establishing biological cycling. Bob Fenner>

Question and comment
UV Sterilizer Use 4/3/09

Hi there from snowy Calgary:
<Hello from sunny CA!>
I'd like to first to say that I'm reading Mr. (Dr.?) Fenner's book,
<He would want just Bob I assure you.><<Yes>>
The Conscientious Marine Aquarist, and it has to be the best comprehensive book on marine aquariums that I have come across. I have already read at least 6 books on this topic, and this is by far the best. It's engaging, thorough, and well-written. Could you kindly pass this on to Mr. Fenner?
<Ah, he reads all the queries, he will see this!><<Thank you Cynthia, Scott. RMF>>
Next, I have 2 questions, and I promised I've looked long and hard but can't find the answer. On page 96 of this book is a discussion on UV Sterilizers. It says that "the UV unit should be the last part of the filtration system before the water is returned..........." and then "......to preserve beneficial microbes and their biological activity." My first question is, why or how does having the UV sterilizer last in line preserve beneficial microbes?
<It does not.>
I thought that the UV sterilizer kills both good and bad no matter where it is in line?
<It does, also stated in the same chapter within the book.>
Second question is, in general, wouldn't it make more sense to have a UV sterilizer on a quarantine tank rather than on the main tank?
<Sort of, it can help. But one of the points of a quarantine tank is the ability to treat if needed with medications. UV is redundant IMO, not needed, but will not hurt either.>
I mean you *know* you're going to get some bad stuff in the quarantine/hospital tank.
Why kill both good and bad in the display tank on an ongoing basis? What am I missing?
<Hmmm, you are not missing anything. I and many of the crew here do not use nor recommend the
use of UV sterilizers. The section in Bob's book is telling people about them and how to use them, not
advocating the use of the contraptions....they do have their place, but not for the average hobbyist in my
Thanks very much,
Cynthia in Calgary
<Welcome, Scott V.><<If I might add... the position of the UV is proposed to allow whatever media comes before it to populate with microbes... It is so, as Cynthia states, the UV WILL indeed "zap" whatever does in time/turn pass by it... Does this make sense? That beneficial microbes WILL still be in, on hard surfaces, slow-moving water... BUT that IF one employs a UV, that it should come/occur last as stated, in the filter/gear placement. BobF>>

UV Filters
<Hi Penny>
I have recently placed an order for a Pentair Aquatics 15w UV filter and am awaiting it's arrival. I am wondering what the harm would be in running it full time? I was hoping to hook it up to my return pump
for full time use. I have a 90 Gallon tank, 2xMP40 Vortech pumps, 30gallon Oceanic Sump, Bubble King 180 skimmer, Quiet One 3000 pump, 110lb LR. I have a Yellow Tang, Hippo Tang, Foxface, and two Perc clowns. I am hoping the UV will fight off disease from starting/ spreading.
<Will aid in this regard.>
I have a UV filter on my 120 gallon pond outside and love it. I am hoping it will be just one more step in having a good, clean and healthy reef system.
<A UV wouldn't be my choice for a reef tank. UV filters are a double edge sword, that is they are non-selective, will kill both good and bad organisms. Do read here and
related articles/FAQ's. http://www.wetwebmedia.com/marphysf.htm>
<You're welcome. James (Salty Dog)>

2/19/2009 UV for tank lighting - Bad Idea Hello, <Hi Andrew> I tried to find some information on using ultraviolet light in the tank for viewing coral at night for aesthetics all i could find is information on using actinic . The light that I was wondering about is an ultraviolet light running at 385 NM. My question is do you think this will be harmful to the coral? I know most actinic runs 420-460 NM. I have mostly a SPS and LPS tank with fish. <Yes,. this would be harmful to anything living in your tank. Metal Halide lights come with UV filters because they produce enough UV light to be dangerous to life in your tank. Please stick to the actinics.> Thank you for your help <My pleasure> Andrew <Mike>

UV Filtration, and algae control f's 1/9/09 Hi all, <Hello> I've got a 60 gallon marine tank - not sure the terminology for my tank design, but basically the 60 gallon tank itself is subdivided into two sections - one for the marine life and the other which is an enclosed ~15 gallon part full of bio balls and a wet-dry filter. <Often referred to as all-in-ones.> The water circulates into this chamber and then is pumped back to the main part of the tank - but it is all enclosed in the 60 gallon acrylic tank. I've got a huge algae and Cyanobacteria problem thanks to a lunare wrasse that has destroyed all of my cleanup crew. <Actually large algae problems are indications of more problems than just a missing clean-up crew. What are you phosphate and nitrate levels? Do you have a skimmer? Is it producing good skimmate? How often do you do water changes and what other livestock do you have.> Despite that, we are trying to avoid parting with our little pain-in-the-wrasse because he is one of the more entertaining fish that we have. <Topping out around 10 inches, the Thalassoma lunare will need a larger tank as it grows.> We are hoping that an UV sterilizer would help us with this - but all the sterilizers I see use an additional pump to force water through a small chamber that contains the UV light. <Yes, is standard setup. However I do not believe a UV will help you much with algae control. It does not do anything for most algaes since they never pass through the filter.> We already have this tank design that effectively cuts down our tank capacity with this back chamber full of bio balls - so is it possible to just set up a bare UV light inside of that chamber? <No, not safe, recommended, or effective.> It is completely enclosed from the rest of the tank with black plastic - so no light should penetrate to the main tank. <I would be more worried about it damaging your own eyes than the tank, these bulbs and do serious and permanent damage to your eyesight. Also the intense UV light would most likely negatively effect the plastic or the filters.> If there is something more to the filter than just the light, I suppose this would not work? <Would not, beyond the safety concerns these filters need specific flow rates to work, which would not be able to be controlled without a dedicated pump.> Apologies if this is somewhere in the FAQ - I could not find it, <No problem.> presumably because I don't know the name of my particular tank setup. In general, is this tank setup reasonable? <Not really, UVs need pretty specific conditions to be safe and effective.> It was a hand-me-down, and perhaps that is why...but despite the fact that we lose a good amount of our tank capacity, it is a pretty simple design and easy for a newbie like me to maintain... Thanks very much for the help! Glenn <Unfortunately tank setups like you have are fairly limited in what they can do, especially within an marine environment. But you can only work with what you have.> <Chris>

Re: UV Filtration, 1/9/09 According to the test kit I have, the levels for phosphate and nitrate are within the desired levels. Nitrate tends to be a little high, but still within what at least my test kit calls desirable. <Numbers here are everything, what the test kit considered desirable may not be.,> The tank came with a skimmer of sorts - there is basically an acrylic chamber in the rear part of the tank (where the bioballs are) where the water enters from the bottom and pours out near the top - at the top of the chamber is a plastic piece with a cylindrical tube coming out of the top - air is injected toward the bottom of this chamber and bubbles out the top. But don't think it is good for much other than making bubbles - I don't see any scum collecting at the top of the tube. <All too common with these style tanks.> So would this be something to add? <Absolutely, a quality skimmer will help immensely.> I had heard these were vital for coral, but did not realize they would help with our situation as well. <I would personally not run any tank without a quality skimmer.> I change 10% of the water every week. <Good> And the two problems are green (hairless) algae (coming from the food I feed my tang I think) and Cyanobacteria (goes rampant really fast). <Is prone to do so, nutrient control is key here. If you have not already please see here for more. http://www.wetwebmedia.com/bluegralgae.htm .> I have two small clowns (2-3 inches), one tiny damsel (1-2 inches), one yellow tang (3-4 inches), <Definitely will need a larger tank> and the wrasse (maybe 4-5 inches). I think the latter is still a juvenile based on the black spot on his fin. We also have a serpent star. <Perhaps not for long.> > Despite that, we are trying to avoid parting with our little > pain-in-the-wrasse because he is > one of the more entertaining fish that we have. > <Topping out around 10 inches, the Thalassoma lunare will need a larger tank as it grows.> At what point would he (and presumably the tang) outgrow this tank? <The problem is that by the time you start seeing symptoms of outgrowing the tank the damage is already done. I would consider moving them sooner rather than later.> > We are hoping that an UV sterilizer would help us with this - but all the > sterilizers I see use > an additional pump to force water through a small chamber that contains > the UV light. > <Yes, is standard setup. However I do not believe a UV will help you much > with algae control. It does not do anything for most algaes since they > never pass through the filter.> > We already have this tank design that effectively cuts > down our tank capacity with this back chamber full of bio balls - so is > it possible to just set up a bare UV light inside of that chamber? > <No, not safe, recommended, or effective.> > It is completely enclosed from the rest of the tank with black plastic - so > no light should penetrate to the main tank. > <I would be more worried about it damaging your own eyes than the tank, > these bulbs and do serious and permanent damage to your eyesight. Also the intense UV light would most likely negatively effect the plastic or the filters.> Ouch - thanks very much for the info then. <Welcome> We had the tank for about 5-6 months before getting the wrasse without significant algae problems - we had 6 turbo snails, 10 hermit crabs, and 10 marguerite snails - but he has killed all but 1 turbo snail. I wish I could figure out why he stopped at that one though - it is still doing an effective job on a small part of the tank each night, but obviously cannot proceed alone. It was the smallest of the Turbos that we bought - but I don't see why that would stop him. <Who knows what goes on in the brains of fish, perhaps he has found prepared food easier/tastier for the moment, but I would guess at some point he'll go after the snail, its just what they do.> We tried a serpent star, but it has proven useless (albeit interesting to watch). <They tend to go for meatier fair.> I thought it would help clean the sand (also quickly infested with Cyanobacteria even a day after I rake the sand), but I guess I was misinformed about that too. <Yep, very little eats Cyano.> > If there is something more to the filter than just the light, I suppose > this would not work? > <Would not, beyond the safety concerns these filters need specific flow > rates to work, which would not be able to be controlled without a dedicated > pump.> > Apologies if this is somewhere in the FAQ - I could not find it, > <No problem.> > presumably because I don't know the name of my particular tank setup. > In general, is this tank setup reasonable? > <Not really, UVs need pretty specific conditions to be safe and > effective.> > It was a hand-me-down, and > perhaps that is why...but despite the fact that we lose a good amount of > our tank capacity, it is a pretty simple design and easy for a newbie > like me to maintain... > Thanks very much for the help! > Glenn > <Unfortunately tank setups like you have are fairly limited in what they can do, especially within an marine environment. But you can only work  with what you have.> Do you have any other suggestions for what we could do? Aside from our enjoyment of the tank, we have a 5 month old boy and he calms down quite a bit just watching the fish. :) <For the time being set up the water changes, preferably with RO/DI water, and syphon as much of the algae and Cyano you can. With time an a bit of effort you will get it under control. Also try cutting back on feeding, many people do not realize they are overfeeding their fish and in the process adding excessive nutrients to the tank, which the algae and Cyano happily use up.> thanks again! <Welcome> <Chris>

Placement of UV Sterilizers 06/24/2008 Good Afternoon whomever is reading this fine evening. <<Afternoon, Andrew today>> I have a question regarding UV lamps and their placement and I was hoping you could help out. <<ok>> Recently I found some 15w T8 TUV (Philips brand) lamps at my work place and it got me thinking on whether or not I could use these lamps in my aquarium. I planned on putting the lamps in a standard 15w light fixture and putting them on top of my refugium (approx 18"tall x 18"long would be the space they occupy) the lamps would be about 8-12" away from the water at all times. My questions are as follows: How far away can these lamps be before they become ineffective? Will adding multiple lamps increase the effectiveness (I have 4 right now)? Will using a reflector increase the light's effectiveness? If i had to put the lamps closer to the water and make a waterproof sleeve; would you be able to use plastic or would it degrade too quickly? <<This should not be done. A UV lamp, in a marine aquarium, should only be used in an enclosed box. UV light itself, if not filtered, can damage>> I know its a bit of a tall order, but researching on the Google has been a little less than fruitful. I'd appreciate any insights you might have. <<Please do read more here to gain a better understanding on how a UV filter works in the marine environment as there are very big differences in use between a UV lamp and a UV sterilizer http://www.wetwebmedia.com/AqBizSubWebIndex/bizuvs.htm >> Thanks, CLB <<Thanks for your questions, hope this helps. A Nixon>>

UV Sterilizer'¦Use Or Not? - 05/31/08 Hello Eric - <<Hi Linda>> One more teeny, tiny question for ye! <<Okey-dokey>> Am getting my things together for the tank and have a nice Turbo Twist 6X UV sterilizer in the garage (amongst many other toys I have collected) and wanted to know if you recommend UV's. <<A pain, in my opinion'¦quite the hassle to keep the units clean/operating efficiently'¦but feel free to use it if you so wish>> I have heard and read many different opinions on the subject, but am sticking to your recommendations to try to avoid any more confusion. <<Ah... (I feel the power [grin])>> Concerned if it would hinder the water flow (which I am trying to avoid as much as I can) because it's just another thing for the water to flow thru, ya know? <<Yes'¦and yes>> Do these harm those nice, little invisible creatures that we can't see swimming around in our tanks? <<At the microscopic level, yes, likely so'¦to varying extents>> (Planning on live rock, fish and soft corals - moving all from 46 gal to this 90 gal., if things work out, that is.) Thank you. <<Always welcome. Eric Russell>>

Do I need a UV and other questions 01/22/2008 Hi everyone.. <<Hello, Andrew here>> Great site! Thank you for ALL of your help. <<Thank you>> I am new to saltwater tanks. I have been following your advice for a couple years after starting a freshwater tank. Now I'm moving into a more challenging adventure! The Saltwater tank! I have a 55 gallon tall tank. 36wx18dx21h. The tank has been up for 7 weeks. Started slowly with 20 lbs. of "local" live rock first. Then added another 50lbs. of "shipped" live rock 2 weeks ago. The tank did a small cycle after the 20 lbs. of "local" and an extreme cycle after the 50 lbs. of "shipped" rock. It has been fully cycled for 9 days now. 0 ammonia, 0 nitrites, 15 nitrates (my LFS says I have 0 nitrates when they tested) .Calcium 360. I have a wet dry filter with bio balls, protein skimmer, 2 retrofit lamps with 96 watt each. (1) blue (1) white, and a SunPaq? 96 watt 50/50 lamp. I also have a Rio 2500 as my return pump (turned down) and (2) 295 gph circulating pumps in the tank. <<ok>> I added 3 damsels after cycle completed a little over a week ago. Two yellow tails and one blue fin. I added a sally light foot and a Mexican turbo about 5 days ago. I had some blue hermits, maybe 3 from the beginning. I also just added a button polyp nugget last night. <<Damsels do get aggressive, you may consider swapping these at some point>> I am currently having a diatom bloom, as well as some type of red bubble algae? Not sure what it is. I can't find a pic of it. My LFS guy came out and looked at it and he said he had never seen it before. It is in the right side of the pic. It is spreading to another rock now. They look like reddish purple capsules. Could you tell me what they are? <<The red algae is Botryocladia SP. Handle this in the same manner as green bubble algae and not pop the pods in the tank.>> Also, could you suggest some reef safe sand sifting creatures to stir my sand bed? (2 inch live sand). <<This will depend on what stock the tank is going to have in there in the future. Cerith snails are good as they spend most of their time rummaging and buried in the sand bed>> Also, does my button polyps look ok? Did I place them correctly? <<The Zoanthids look very nice indeed. Look fine where they are>> My LFS told me I need to get a UV sterilizer. They suggested a Turbo Twist 9 watt for my tank. Says it will help with my algae and potential ich problems. Stated that it will not cure ich, but it will help it from starting. They also had me add a ground probe into my sump for electrical currents. They are willing to sell me the UV at the online price that I have found at $80.00. They sell them in their store for $150.00. Should I run it 24/7? Or should I just run it during daytime? <<Not a bad price for the UV. Personally I don't run them, never have done and don't feel I need too. Never suffer water quality issues without one>> I REALLY appreciate all your help! I am so confused with all the different info I keep getting. I am sorry for all the mixed questions! You guys and "girls" are great! Thank you! Raesunrae <<Thank you for the questions, hope it helps. A Nixon>>

UV Sterilizer Application -- 11/13/07 Hello Eric, Bob and Crew! <<Hey there Don!>> My wonderful question today is what choice you guys/girls would do for a 210 AGA Mega Slow. <<Mega 'Slow'...Ha! I get it! Good one!>> I have an EV-240 with Mag18 pump in my 135 gallon sump. I have a section cut off for refuge and a 7 inch DSB with 50# LR. To help with Crypt outbreaks and I completely understand this isn't a cure all but I'm trying to figure a best fit scenario. A) Corallife 36 watt UV connected to a proper pump and let all the filtered water go through the out take to the tank. B) Buy 3 separate Corallife Twist UV's and place 2 9 watt UV's in the Mega Slow over boxes and still do option A with an 18 watt Corallife Twist UV. C) Stop being an idiot with crazy ideas, buy a UV and just stick it in the sump. <<I'd just choose the simplest approach (likely 'C'). I'm not a big fan of 'Hobby use' UV units, I find them to be too fiddly/high-maintenance to keep them working efficiently and for the 'little good' they may do re Crypt control. I would rather spend the bucks on a quality ozone unit for its increased benefits to the system...and rely on my own good husbandry/quarantine/hospital technique for pest protozoan prevention/treatment>> Thanks again for your time. Don V. <<Always glad to proffer an opinion. Eric Russell>>

Tangs Getting Ich -- 9/24/07 Hi, i am thinking of purchasing a yellow tang for my reef tank. will a UV Steriliser STOP it from getting ich or will it just help it. <The latter. Bob Fenner>

UV-C Light Exposure 9/13/07 Hi, <Hello Mark> I have a 110 gallon marine tank with a 1000 gph through a 40 gallon sump. I have an additional 500-3000 gph flow on hand in the tank itself. I have added a 7 watt uv-c sterilizer bulb in quartz sleeve (JBJ Submariner 7watt) submersed directly in a chamber of the sump without housing and pump (watts). I know that I should not directly look at it and have the door sealed and locked to prevent accidental exposure when it is on(2-3 days out of a week). Is this O.K. or beneficial? I figured whatever flows by the light and may die over time is better than nothing. Is the light comparable to someone arc welding? Is a little exposure O.K. , 2-3 seconds, till I get it shut off? Please give me your valuable opinion if time permits. <Mark, do not know if I understand your query. Are you saying the bulb is directly visible, that is, it is not enclosed in a housing of some kind? If the bulb itself is directly visible, by no means look at the light for any length of time. I'm thinking you removed the bulb from the housing itself and are using it as such. Doing this dramatically decreases the effectiveness of the lamp to water borne bacteria. As the danger of UV-C rays, read here. http://rds.yahoo.com/_ylt=A0geu5_ aTOlGrgMA21dXNyoA;_ylu=X3oDMTE5dmo1Ym1yBHNlYwNzcgRwb3MDMwRjb2xv A2FjMgR2dGlkA0gwMDdfMjAxBGwDV1Mx/SIG=12slpp68t/EXP=1189781082/**http %3a//www.hygienitech.com/Hygienitech%2520UV-C%2520Light%2520Primer.pdf> Thank you for your time, <You're welcome. James (Salty Dog)> Mark.

Bubble Algae/UV Sterilizer - 10-30-06 Hello Mr. Fenner/WetWebMedia crew, <<Hello...Eric Russell here today>> I have just discovered a few pieces of bubble algae in my 110 gal aquarium.  The bubble algae was perfectly round and very dark green in color. <<A species of Valonia likely...not uncommon>> I manually removed them however one popped and I bet I will be seeing more in the future as spores were most likely released. <<Possibly...to what degree depends on how "suitable" your system is to harboring these algae>> A water test shows my nitrates are high (40 ppm). <<Yikes!  Indeed so if the test kit is accurate>> So, I know I need to work at lowering nitrates.   <<Yes...do start reading here and among the linked files at the top of the page: http://www.wetwebmedia.com/nitratesmar.htm >> I was thinking about purchasing a UV sterilizer which I think would kill algae spores with the additional benefit of killing parasites. <<I'm not a fan of these units on reef systems as they are too indiscriminate, but they can be of benefit for FO and FOWLR systems if you're willing to keep up with the high maintenance of these units>> However, I am concerned that using a UV sterilizer may reduce other algae which my lawnmower blenny eats. <<It will>> For now I will continue to manually remove any bubble algae I see as well as reducing the nitrate level. <<May be all you need do.  A possible biological control to this species of algae, in my experience, is the Foxface (Siganus sp.)...if your tank has room for the additional bio-load of course>> Do you think the UV sterilizer would help me here? <<Possibly>> And if so, what wattage would you recommend for a 110 gallon tank? <<I'd go with one size up from whatever the particular manufacturer suggests>> Thanks, BobbyG <<Regards, EricR>>

Tangs, Crypto and UV - In Other Words "QUARANTINE"! (5/15/05)  I have 3 tangs in my 125G tank, and they are all getting along very well. Rarely see a raised fin, tail slapping, etc.  <Lucky you. It may not stay that way as they grow.>  That said, two are the most common contractors of ich, the hepatus and the powder blue.  <Yup.>  My reef has way too much rock with coral frags all over to dig out. If I wanted to be proactive, what is the best way to make sure ich does not enter the picture.  <4 weeks of quarantine for any new additions. Make sure they get a good variety of food with plenty of algae. Supplement with vitamins and HUFAs, which may help prevent HLLE, a big problem with the Hippos. Keep system as stable as possible. Minimize stress. Remove aggressors if problems do develop eventually.>  I do weekly 15% to 20% water changes, aggressive skimming, etc. Occasionally I'll see a tang scrape against a rock a time or two, but I always hope it was just an itch.  <If this is occasional, it is probably not a concern.> Bottom line: do UV Sterilizers, large enough with a slow flow rate, eliminate ich with destroying too much beneficial stuff?  <No guarantees. It may help and some people run it periodically or continuously, though there have been unsubstantiated concerns of this leading to immunodeficiency in the fish. For a great summary of UV pros and cons, read Scott Michael's marine parasite article in Aquarium USA Annual. It was the 2004 Edition, I think.>  Thoughts on the best way to avoid problem before it starts?  <As above.>  Thanks.  <Hope this helps.> 

UV sterilizer, using WWM Good day, <And thou> I firstly want to say that I think you guys are the best! <What about the gals?> I have had problems with whitespot disease (a couple of times) in my marine aquarium in the past.  A chap at one of our local fish stores sold me a UV Sterilizer and told me that I should not have to worry that my livestock would get the whitespot disease again, <Wrong...> if no new livestock was added without being quarantined. <Oh!?>   I have a 250 Litre aquarium.  The UV sterilizer is a 9 Watt unit and the manufacturer states that for my aquarium size I only have to operate it for 7 hours and 30 minutes a week, passing the water through it at a rate of between 100 and 190 litres per hour. <No... needs to run continuously...>   I have installed it with a timer, to operate it for 1 hour and 15 minutes per day at 150 litres per hour. Is there a best operating period of the day (Day time or Night time)?  Is my set-up correct or must it only run one day of the week continuously for 7 hours and 30 minutes? Thanks. <Please... read... on WWM re... starting here: http://www.wetwebmedia.com/UVFAQs.htm and the linked files above. Bob Fenner>

Hermit Crabs Hello crew. I have two questions. When my SW hermit crabs molt, should I clean up the remains.  <It's not necessary, you can for aesthetic reasons.>  The other question is about UV sterilizers with live rock. I have read that they kill off organisms that the rock produces, but have seen many tanks with LR and sterilizers. Thank You for any words of wisdom.   <UV sterilizers will only kill what goes through them.  So, if you should have a pod population, any of those critters taking the ride through the UV will be zapped.  James (Salty Dog)> UV and Quarantine (4/2/05) I am currently cycling a 52 gallon marine tank with cocktail shrimps... <Do you plan to eat them? Sorry, couldn't resist. I am not familiar with an aquarium species referred to as "cocktail" shrimp. I've only heard of the ones you buy at the grocery store.> ...and it seems essential that I also have a quarantine tank (perhaps about 20 gallons).  <Yes!>  There is a lot of information on your site on the details of this, and how long to keep fish in there (21 days on average for trouble to show up).  <More precisely, if you have gone 3-4 weeks without having problems, then it's unlikely that any will crop up after that.>  Many people who have submitted questions are in damage control scenarios by not using quarantine tank initially, hoping that an UV sterilizer would help rid of a disease problem in a display tank (if only it were that simple!)  <Hear, hear.>  Are there significant cost effective advantages in having a small UV sterilizer up and running in a QT from the moment the fish are put in there for their three week stay in the hope that this may stop any potential disease outbreak that could develop in the first place?  <UV sterilizers are rather expensive, so I doubt that one could call them cost-effective in this scenario. That said, I will not deny the potential benefits of UV--I use one myself on my display tank. Using it in QT seems better as part of a treatment for infection, rather than as a "preventive." If infection is noted as part of initial quarantine, one could consider UV as part of the treatment, but I doubt it is cost-effective compared with the many relatively inexpensive medications available.>  All the Best. Mike Lomb  <Same to you. Steve Allen.> 

UV Sterilizer Effectiveness in Marine Aquaria  12/04/05 I plan to put a 110w TMC commercial UV sterilizer on my 220g fish only with live rock tank. <Okay.> The manufacturer states that the unit operates at 30,000 uWS/cm2 @ 1020 gallons per hour. <It's a biggun'.> I know this is effective to kill bacteria and algae, but what about protozoans like ich and velvet? <Simply put am Ultra Violet Sterilizer will only kill watt passes through it this includes the good and the bad. It is not effective at solving a parasite problem (full eradication/disposal), simply because the chances of every individual parasite passing through it is so low.> I understand that UV is not very effective at eradicating a parasite, <Right.> and that it does little to the tomite phase. But at what uWS/cm2 is UV helpful in controlling the free swimming stage of protozoans? <The ones that pass through it (the UV). Of course, as I'm sure you know, if you have an out break in the display the best way to treat is to remove the specimens to a quarantine tank. As far as UV usage lets just say there are mixed reviews. I have one but use it only on occasion and in emergencies, such as unexpected algae blooms (a small Caulerpa reproductive event in this case).> I've referenced several sources and tables but none mention this exactly, just the tomite exposure. Thanks, <Welcome.> Brandon Hathcock <Adam J.>

To UV or not to UV - That is the question.  12/9/05 Dear crew, <Hello, Adam J with you today.> I was planning on the purchase of a UV sterilizer for my live rock reef tank containing soft polyps, snails, hermit crabs, cleaner shrimp and various "reef-safe" fish. Everything is fine. Will a UV sterilizer be beneficial or can it possibly hurt the balance in my tank? <I think the important thing to know about U.V. units is that they do not discriminate. Whatever passes through them will be killed, whether it be good (microfauna) or bad (pest algae and parasites). For this reason, as you mention below, there are mixed reviews. They are not necessary to mandatory by any mean but personally I think it is nice to have one for emergencies such as "algae" events of epic proportions and while they are not efficient at eradicating a parasite they are a good tool. I only run mine occasionally (when pruning algae or new introduction of an animal.> It seems I've read views for & against. Please help!  <Overall they are a nice luxury but not necessary.> Thanks, Wayne Oinonen <Adam J.> 

UV Sterilizers for ballast water - High School Robotics Team Query (Exciting!)  11/18/05 Hello there, <Hi there> You all have been so helpful to me in the past. Thank you again! My question this time is not really related to aquariums, however I am hoping you can point me in the direction I need to go. I have been reading all that I can find on the UV sterilizers for fish tanks.   My son is on a LEGO robotics team. Every year they are given a mission.  This includes making and programming a robot and also a research project. This years mission is an Ocean Odyssey. The research project they have chosen is how ballast and bilge water can carry organisms into foreign habitats and how to solve this problem. They have come up with some ideas, the UV sterilizer being one of them. They are trying to find out if this could be a practical solution.  <I do think so... not toxic, but useful for "zapping" micro-organisms, producing ozone.... which also has a sanitizing effect> The cons in Bob Fenner's article Protein Skimming, Ozone, and UV Use in Marine Filtration do not cause a problem in this usage. Any help or ideas would be great! Thank you, Cindy Haralson for the Polar Bears Robotics Team Kenai, AK <You go team! Bob Fenner>

UV Light 11/3/05 Hello guys, <... and ladies...> I'm thinking of using UV light to fight algae bloom in aquarium but I have a macroalgae which is Caulerpa and I don't want to hurt it. Will UV light hurt it? <Mmm, nope> Also what's the suitable UV light in terms of power (watts) for a 4'x2'x2' tank.  <<The one that exploded..???>> Your advice is very much appreciated. Thank you. Sam Malaysia <Depends on flow rate through the unit... but likely more than 40 watts is not useful. Cheers, Bob Fenner> 

Re: 125 Gallon Aquarium - Proper Fish Selection... actually ongoing vague questions that are sufficiently covered on WWM    5/24/06 Thanks again Bob.  I believe the UV sterilizer will help control parasites on fish such as tangs, correct? Ryan Mullinax <Can help, won't cure. Bob Fenner>

UV Sterilizers...Too Much Wattage?  - 05/22/2006 Hi gang, <Hello Sam> I just recently bought a 57 watt UV for my 120 gallon. it's a FO. I heard 40 watt was ok however, my aquarium maintainer said 57 watts is ok. What do you think? Can you have too much UV light? <Nope, the higher wattage allows for higher gph rates/larger tanks.  The downside in using higher than required wattages is that you are adding more heat to the system. Thanks, <You're welcome.  James (Salty Dog)> Sam Nitrate Control    3/29/06 Dear Bob!  <James today.> Can a UV sterilizer make the nitrate level lower in an only fish saltwater aquarium?  What do you think? <Won't do much for you in that regard.  A good protein skimmer will help.  Read here also. http://www.wetwebmedia.com/nutrientcontrol.htm> Thank you for time!  <You're welcome.  James (Salty Dog)> Sonny. UV Sterilizer... to UV or not to UV that is the question , alg. cont.   3/15/06 Ok I have a 220 gallon tank that has a real nasty algae problem, the water has turned this murky green I can't see my 3 fish unless they swim up to the front next to the glass, or the back of the tank I have tested my phosphates and it was at .5 so I added Phos-ban  or Phos-guard, not sure what it's name was yesterday, The history of this tank is this, there was a ick outbreak, put fish in QT treated fish there and treated main tank with lower SG 1.009 and Cupramine. After the treatment I put carbon filters back into my 3 powerfilters and turned on my protein skimmer and started to raise the SG back up to normal. well after a few days my water started to turn this cloudy greenish/yellow color. <The algae taking "advantage" of an unstable, predator-less environment (you bumped off most all of the microscopic algae eating life)> I have done several water changes on the tank doing as much as 45 gallon changes and the green water is still there. I think it looks worse since I did the water change this last time.  I have power heads with air stones to bring in air to the water since I have this huge algae bloom. Here is my question. I have been told that the only way I will be able to get rid of this is with a UV sterilizer. <A good part of it... likely so> It will keep the green water away permanently. <Mmm, maybe... if you have circumstances that otherwise don't favor this> I'm not sure if my LFS is trying to push me to buy or is actually giving me good advice. I have so much tied up in this system at this point I would really like to enjoy it. Would a Gamma UV 25 Watt sterilizer be enough for my tank size? <A good start... actually more watts could go here> Doctor foster and smith have it rated for a tank of 500 gallons with a max flow rate of 2000 gph. Thanks for all your help on this. <Mmm, before buying I would read over the materials posted on WWM re UV use in marine systems, algae control... Bob Fenner>

UV sterilizers  - 03/11/2006 Do you know much about  UV sterilizers <Some...> Do you recommend the use of  UV sterilizers in home aquariums <Please read here: http://wetwebmedia.com/UVFAQs.htm and the linked files above> I  hear they work well in controlling  parasites such as ich . <Can help... but won't eliminate their possible introduction, spread... See...>   Is it true. Thanks for responding <Bob Fenner>

Algae Control...UV Sterilizer   7/7/06 Hello, <Hello Joseph> Just in the past few weeks, my tank has started to accumulate green algae all over the tank (green water).  My tank is right at the entrance to our backyard, but does not get DIRECT sunlight because we have a huge canopy covering majority of the backyard.  I've done approx. 20% water changes every other day for the past few weeks, however, the algae just keeps coming back. The water parameters are ammonia/nitrite 0ppm, nitrates 10ppm, ph7.2. Because the tank is outside, I'm figuring a UV sterilizer might be a good buy in this case?  Please bear with me here:  I have a 40 gallon tank, Marineland Penguin 350b power filter that filters 350gph.  I'm looking at the Coralife 9watt UV sterilizer which has a flow rate of 100-200gph.  Would this be compatible with my Penguin power filter?  Are there any correlation between the flow rate of the power filter and the flow rate of the UV sterilizer. <The flow rate of the UV means, for an effective kill, the flow should not exceed 200gph for this model.  You would need a power head rated at 200gph or less, to pump the water through the UV.  I would install a sponge filter on the power head, such as Hagen's, that is designed to be used with power heads.  Much better to pump clean water through the UV.> Any recommendations on whether it would be best to use the UV sterilizer as inline with the filter or hang-on-back and how would you recommend hooking up the UV sterilizer? <Your Penguin would be of little use feeding the UV as there is no way to attach tubing to it.  As above, a power head will be needed to feed the UV. The UV will not do much good killing algae already growing in the tank.  All it will do is kill water borne algae spores.  Outside lighting, even though indirect, will greatly enhance algae growth.  You may be fighting a losing battle here.   Controlling nutrients in your system will help also.  Read here along with related articles and FAQ's above title bar. http://www.wetwebmedia.com/algaeconMar.htm Even though it is a marine topic, it does apply to freshwater also with the exception of protein skimming.  A Pleco in the tank will definitely help control the algae, but it would soon outgrow the tank.  James (Salty Dog)>      Any info/help would be very appreciative! Joseph

Angels and UV sterilizers and Monkey crap After I added live rock to my tank, I have unable to keep any type of angel fish longer than two months. My LFS made the following comments to me today: "If you have live rock, angel fish will get coral reef disease and not last more than two months. The only way to keep them alive is to use a UV sterilizer." <that explanation from your LFS is not only the biggest pile of steaming monkey crap that I have heard in weeks, but also the most shameless yet creative sales strategy for selling UV sterilizers that I have ever heard of. Did they explain what it is in live rock that specifically kills angels after the magic 8-week time-elapse (they need to come up with a much better explanation than a mythical "coral Reef Disease" to temper their "Pinocchio Disorder") or how it is that angels in the wild survive while living on and in live rock?!?! Furthermore, what is it that the UV does to correct this?> I was able to keep a bi color angel alive for several years when I had only lace rock in the tank. So maybe he is right? <he couldn't be any more wrong with an honorable mention for being patently ignorant or patently fraudulent. Did it cross your mind that maybe the problem with your angels is the source (ahem...)> Also, won't the UV sterilizer kill some of the good micro whatever stuff in the tank? <not really... and it also does a rather poor job of killing parasites in display tanks too as evidenced by the sick angels purchased from this LFS...heehee.> Thanks for your time. <May I suggest that you be certain to QT all new fishes from a full 4 weeks and also consider that bicolor angles are rather difficult to keep to begin with and that most seen in the trade are stressed and or drug caught Philippine specimens. They only cost about $6 wholesale which is why some retailers like to keep selling this challenging species... tempting profits. I'd reconsider the species overall despite your previous success and I will say that live rock will be necessary to keep this fish more than 2 years in captivity with less fear/concern of death by dietary deficiency. Best regards, Anthony> 

UV Filtration I recently upgraded from a 55 to a 90 gallon aggressive tank with abundant live rock (125-150 lbs), live sand (30 lbs?) and a small, happy & healthy community of creatures.  I am using a Fluval 402 canister filter and will be upgrading from a Red Sea Prism to a AquaC Remora Pro H/O filter.  As I am fairly new to the hobby, I am quite happy keeping less exotic, hardy species, but of course I would like to practice the best husbandry possible.  <<Hi Thomas! Craig Watson here answering some of Bob's inquiries while he attends the MACNA conference in Fort Worth. Nice upgrade on the skimmer, you won't regret it.   Wise to progress as you learn!>> My question is this:  is the UV filter going to be useful for me?  My thinking is that it would stabilize the environment during the stocking phase, as I will be adding several fish in the next few weeks. Your responses to FAQs regarding UV filtration seem to suggest that its usefulness is limited and that it might actually remove useful microorganisms as well as potentially harmful ones.  It strikes me that this is similar to the use of antibiotics to treat human disorders, which leads me to wonder:  is it possible to use UV filtration in a limited way, i.e. not to leave it on the system permanently, but rather to employ it when needed?  For example, would it make sense to put my UV filter on the tank in anticipation of acclimating new creatures, then only leave it on until they've been fully assimilated into the community?  Also, would it be useful to keep the UV filter handy in case of unexpected problems arising?  If so, when would it be appropriate to deploy it? <<I personally do not use UV.   I, like Bob, think it has limited usefulness.  There are others that endorse it strongly and swear by it.   Each group has what could be defined as success. I don't see UV helping you when stocking.  I can't recommend strongly enough though, the use of a quarantine tank for all new inhabitants. You can read about quarantine on WWM. The biggest issue when stocking is not overstepping your bio-capacity and UV can't help you there.  No fish should be stocked until after a proper quarantine. There are situations where UV can be helpful, but these are usually situations best avoided by proper husbandry and care. UV is routinely used for infestations if ick, velvet and other parasites.  While it kills these organisms in the water column not all of the organisms make it to the UV for treatment before they attach to rock, tank or substrate to then find a host.  Quarantine and treatment resolves this before it becomes a problem. UV is also used for algae control which could be better accomplished with clean nutrient free source water, nutrient export, skimming, filtration and feeding the correct amounts and types of food. I personally wouldn't use UV on a constant basis or go out and buy one, but if I had it and I had one of the aforementioned issues it wouldn't be harmful to use it temporarily. If it's new in the box and you could return it, I would invest in a nice QT tank which you will need and use more than the UV. I hope this helps, Craig>>

Re: UV Filtration Craig, Thanks for the helpful comments!  I think I may return the UV filter, after all. I wonder if I might trouble you for some more advice?  I would like to simulate a dawn/day/dusk lighting cycle and it seems like the best way for me to accomplish this would be with two 24" tank-top fixtures, each containing two bulbs with separate power cords and controls.  I could get away with a single 48" fixture, but it would be less convenient for working in the tank.  Anyway, the only ones I've been able to find so far are by Custom Sealife and they are quite expensive.  Since my tank is not a reef set-up, I don't know that I need the very best in lighting.  Would you have any more reasonable alternatives to suggest? Appreciatively, Thomas <<Hi Thomas, How much do they want for the 24" fixtures? Do you want a dimming dawn/dusk display or do you just want the lights to come on and go off in stages? If you want a true dimming cycle you should look into an Ice Cap ballast with a dimmer.  This actually dims the fluorescent lights. You can see them at http://www.championlighting.com/ or Marine Depot http://www.marinedepot.com/ There are of course other retailers as well. If cost is an issue, and of course it is for most of us, then you can go with multiple fixtures or one fixture and timer(s) without the dimmer. A good place to look for something like the CSL would be AH supply at: http://ahsupply.com/ Hope this helps! Craig>>

UV Use Hi, I wrote a couple of weeks ago about a 300 gallon fish only tank that would not clear up (very Cloudy) Your recommendation was a UV sterilizer. It worked great. Now my question is how long do I keep it on the tank? <Indefinitely> I'm getting ready to add some live rock. Will this effect the rock or the algae growth on the rock? <Won't affect negatively> Should I remove the UV or let it run Its been running about two weeks.   Thanks Again for your help, Rob <Thank you for your query. More questions re these physical filtration devices can be found archived here: http://www.wetwebmedia.com/marphysf.htm and the linked, UV FAQs beyond. Bob Fenner>

UV sterilization and live plankton What if any effect does U.V sterilization have on the live plankton I put in my tank for my corals? <much, most or all of the plankton that passes through the unit will be killed depending on the flow through rate (and efficacy of the set-up). UV is not recommended on reef tanks. It should not be necessary for disease control with proper QT of all new animals, and it should not be needed to temper green water with adequate nutrient export mechanisms (skimming, water changes, etc). UV's are commonly mis-sold for disease control yet they fail regularly due to improper installation. They need a fine polishing mechanical prefilter on the inlet, tank water needs to have aggressive clarity control (weekly carbon or daily ozone), the contact chamber needs a very slow flow through and a monthly purge to reduce mulm and other built up organics, and the bulb needs to be changed approximately every six months. And even when all of this is done... it can only kill what flows through it. Many larval parasites settle to the substrate and can rise and attack fishes before being drawn into the UV. UV are best run on bare glass bottomed aquaria for this and other reasons. Best regards, Anthony>

Re: new reef tank issues Hello Craig. <Hi Steven,> I do not have a secondary tank to quarantine the damsels. Will a small U.V sterilizer work? I am told it will eliminate the ick, but will also damage good organisms.  <No. Will kill Ick in water column but cannot circulate all the water in all the various crevices and such...so Ick will remain as long as there is a fish host (which the UV can't cure either). You can purchase a pretty nice QT set-up for the price of an ineffective UV.>  How long should the light be on ?  <Your main should run for twelve hours, it has corals that need the light. You can keep a QT for fish bare and dark (with a few plastic plants and places to hide). Do scrap the UV idea, it won't eliminate Ick> Can I add corals such as brain, clams, torch, etc. with ick in the tank once it has completed cycling?  <The Ick will not affect any other aquarium inhabitants but fish. Please keep in mind that Ick could come in on corals and rock kept in systems housing fish, so are to be QT'ed too.>  The only residents in my tank now are some snails, a couple crabs, and some things (polypus I think) growing on the live rock. <No worries there.> If the tank is without the infected fish for 1 month, will that be the end of the ick life cycle in the tank? I appreciate your ongoing help. Steve. <That is the life cycle. There are some particularly "virulent" forms that may persist, but if you read the links to disease, you will realize that the month fallow should be spent improving the conditions that led to this spike of Ick in your marine environment. To prepare for returning fish perhaps you should look into some cleaner shrimp and gobies to get after any remaining stress related outbreaks. You can check them out at Aquaria.com, or any of the other livestock sponsors of WetWebMedia.com. Sure hope this helps! Craig>

UV Sterilizers In Reef Tanks Good day, Frank here. <Scott F. here this afternoon> Do you think that UV Sterilizers will help my reef tank in brown alga bloom and hair alga ? <Probably not. They are effective at reducing unicellular algae, but I think that nutrient export/reduction is the key to removing the algae that you mentioned> Although I had use phosphate remover and MH light been used. Is MH light cause more alga problem than fluorescent lamp (NO, HO, VHO)? <Well- it's really not the light, in and of itself. It's the light in conjunction with high levels of nutrients, such as phosphate, nitrate, silicate, etc.> As far I know is that UV will kill bad and good floating bacteria, (phytoplankton - food for coral) that by pass it. So for bacteria in liverock and live sand, the UV will not have opportunity to kill it. right? <That's my opinion, too> Algae is a floating type , so my tank will have less brown alga on my front tank and hair algae if  I use UV Sterilizers? <Again- I think it's more a function of nutrient reduction. You will not see as much "green water" in a UV-equipped tank, but I don't think that there will be a noticeable reduction in hair or brown algae... You should work on improving water quality through efficient protein skimming, water changes, using quality make-up water (RO/DI), and careful feeding> That means also if I use UV, I will have to feed my fish and coral more, if not their will suffer from floating food in the water. <Well, I don't know about them "suffering", but UV use can alter or reduce populations of natural plankton in aquariums> Hope my question not confusing you ... Thank you. <I hope that I was able to clarify some things for you. Good luck!>

Hope I did not waste my money Hi! I want to thank you guys for your website. It's nice to get some good consistent advice. <Thank you very much!> It seems like every time I listen to my LFS's I end up with more problems. <That is a shame. Perhaps look into another store in your area. Also, try to locate a local marine aquarium society. Here you can find many educated opinions on the local stores, expert advice from seasoned aquarists, and good friends.> And the result being that I have transferred lots of money, from my wallet to theirs without making much progress. <But on the other hand you are helping to keep the economy humming :)> In reading your FAQ's I have noticed that you don't seem to mention the use of the UV sterilizer for the control of the parasites that cause ICH. <Correct. They are too often misapplied when a proper quarantine tank and protocol is much more effective and cheaper, too.> I have recently set up a 300 gallon fish only with lots of live rock. My approach to controlling the parasite problem is: to maintain a SPG of 1.015, <Wow! Pretty low for liverock. I prefer to attempt to replicate an environment closer to nature.> use cleaner shrimp, <I am surprised your shrimp are surviving. I also don't put a lot of faith into the cheap box hydrometers we all use. Your 1.015 reading could be 1.012-1.018 in reality. Calcium deposits, banging them around, and other activities mess up the measurements.> a 1-1/2" French Angel (as a cleaner) and a 120 watt UV sterilizer. I have very good circulation, using a Iwaki MD100RLT. I get about 4 to 5 turns per hour though the UV. <Your UV gets that much water through it! As long as you are following the manufacturer's specifications for effective kill rates of protozoans, you should be ok.> Did I waste my money going with the UV or did I do a good thing?<I would not say you wasted your money, but do not let the UV lull you into a false sense of security and add unquarantined fish to the display. Also, be sure to keep track of all the maintenance (replacement lamps, cleaning the quartz sleeve, polishing the water to ensure maximum UV penetration through the water, etc.). UV's are very labor intensive.> Thank you, Rick <You are welcome. -Steven Pro>

Re: ecosystem 60 and UV sterilizer I am getting conflicting thoughts from two local pet stores.  A small well run local store says it's ok to run an ecosystem 60 and a UV sterilizer together in series for filtration.  A local chain says that you absolutely never want to run a UV sterilizer period.  Unless there is something wrong in your tank.  He says that unless there is a presence of disease or a problem, a UV sterilizer should not be used.<They're nuts!> I need a professional impartial opinion.<Your about to get one!> I currently have a 55 gallon saltwater tank that I'm looking to setup more professionally to get better filtration.  I'm currently running a "Skilter" which is a mechanical filter and protein skimmer device.  It was relatively cheap and when I got started 5 years ago it was an economical decision.  I have probably 10lbs of live rock and only a few fish presently but before I add more I want to just get a better setup going. It's my understanding the EcoSystem 60 will significantly reduce the need for water changes and provide better overall filtration. Your response will be greatly appreciated. Thank you, Jeff Longmore <Jeff, let me start off saying that a U.V sterilizer can be used in a tank no problem.  But don't think it will solve all sickness problems etc. etc. it will help.  I must say though, you should look at updating your skimmer before adding a U.V sterilizer!  I've use Skilters and find them "iffy" at best.  A good skimmer would be much better!  A good skimmer should produce dark skimmate almost everyday!  The EcoSystem 60 will help with water changes to a point, but it's still up to you to do monthly or bi-monthly changes!  Go to www.wetwebmedia.com/marphysf.htm for more reading!  Hope this helps!  Phil>

Re: ecosystem 60 and UV sterilizer Wow!  Thank you for your prompt response!<No problem> I'm about to check out the link but as usual I have more thoughts and questions. Is the UV Sterilizer something that should/could be left on all the time?<You could leave it on all the time!  But it may not be needed> Could you recommend a quality skimmer for my 55 gallon tank.  Does the skimmer run all the time?<I run all my skimmers all the time!  I like Aqua-C, it would be great in a tank your size.> Unfortunately, I'm not terribly familiar with how a better setup like this should operate.  I know I want to improve the overall way my tank runs and is filtered to make it as low maintenance as possible.  I figure I'm willing to sink as much as $1K into it.  If there are more natural things I should be doing, like adding more live rock or plants or something I'd like to know so I can enjoy the hobby more. Thank you again, Jeff <Your best bet is to add more live rock, but not too much as this is not a reef tank.  I would say add another 10-15 pounds over the next few months, be sure to qt this rock!!!  Get a skimmer as I said before.  You don't need a U.V sterilizer really... if you want one, get it... I don't run them on my tanks.  Only on my pond.  What type of filter are you running, that plays a big factor in water filtration!  What kinda sand bed do you have?  That also plays a part!  E-mail me back w/ more spec's of the tank and what's in it and what will be going in it!  The more I know the better!  And this will not cost $1k if you do it right!!  Phil>  

To UV, Or Not To UV? Thanks!  Regarding UV, by the way, I know you are supposed to turn it off when using meds.  When can you turn it back on?  Can you do a water change, replace carbon filter, and turn it on?  Or do you need to wait a while, and if so how long? <I'd turn it back on after the change, myself> Since I'm on the subject, what about when using plant fertilizers like Flourish, products like Melafix, etc.? <I would not be as concerned about the plant foods, but with medications, I'd refrain from the UV usage> Thanks! <My pleasure! Regards, Scott F>

UV vs. Skimmer Dear Crew: What an awesome group of people and a terrific website!!!!!!!! The only downfall is you can find yourself at the computer screen for hours on end!!   Great reading.  Keep up the good work. Hoping you might answer whether I need any additional equipment. Current setup is a 150 gallon Marine Tank, 1 year old.  Fish Only. 1 Large Clown Trigger, 1 Picasso Trigger, 1 Blue Tang, 1 Sail fin Tang, 5 Yellow Tang, 1 Naso Tang, 1 Mexican Rainbow Wrasse, 12 Damsels, 2 Tomato Clowns.  All are doing very well.  Feeding Seaweed sheets, Brine Shrimp, Formula 2 and periodic Squid etc. The tank has numerous dead coral pieces.  I am cleaning the tank at least every 2-3 weeks due to the coral, powerheads, glass etc. building up with brown algae.  Bleaching and elbow grease always solves the problem.  Question?  Can the brown algae buildup be cut down with additional equipment such as a UV sterilizer or a protein skimmer?  The current equipment setup is:  @ wet/dry's (stand wouldn't accommodate one larger one) Three cabinet setup.  1 Wet/dry on each side.  2 Magnum 350's, 1 with pleated filter, 1 with carbon in the middle.  4 x-large powerheads in tank, 2 spread out on each back side of tank.  Circulation only w/ 1 bag of carbon in each powerhead strain canister.  Lot's and lot's of water movement.   After each cleaning within a day the tank is crystal clear but generally erodes within 3 weeks.  In addition to more frequent water changes (25%??)also how often? is their anyway of lowering the algae growth? PS: I have been using tap water with chlorine etc. remover.  How important is it that I start using Distilled water? Also, is there anyway of brighten up white coral?  Does it brighten more with bleach or sitting in the sun?   What is a good rule of thumb for bleaching and cleaning Dead Coral.  Thanks for any help you can provide!!  Lane   <Hey Lane, a good skimmer would definitely help in this situation, you have a heavily stocked tank and some messy fish, the skimmer will help to remove excess nutrients from the water.  Take a read over our skimmer section for more information.  The tap water could also be contributing to the algae problem, it may have a large amount of phosphates or other nutrients to help the algae grow.  Distilled water will cost you a bundle if you are doing 25% weekly water changes, you might consider looking into an RO, DI, or RO/DI unit.  I have heard good things about the Kati and Ani system from DrsFostersSmith.com. I have not had to do much coral bleaching, I'd say a good dose of bleach and water solution should take care of it, 1cup (straight bleach, no perfumes or dyes) per 5gal of water.  Maybe more bleach, be sure to give them a good rinse when done and let them dry in the sun to dissipate the bleach.  Best Regards, Gage>

UV vs. Skimmer Gage: <Hello Lane> A UV Sterilizer wouldn't be worth my time? <Not compared to a good skimmer, both would be nice, but if it were me I would save the money from the sterilizer and put it towards a better skimmer.  The better you skimmer is, the better your water quality will be, and the less things (algae, bacteria, parasites) you will need to zap with a U.V sterilizer. -Best Regards, Gage>

UV light - good for flukes, Ich and velvet (marine tanks) <Hello again Luke>I have one 35 gallon tank (marine) and I'm planning on putting Coralife Turbo-Twist 3x UV sterilizer, which they say is good for up to 125 gallons. <Seems a bit of overkill on your size system> The flow through the sterilizer will be 150gph. I'm wondering, if at this dose will the UV light also kill flukes and marine Ich and Velvet? <Well, I haven't really heard that flukes are a common problem, such as ich and velvet are. As for them, yes the sterilizer will kill their larvae. But, that might not prevent an outbreak, or an ongoing infection. Such diseases have more do with a lack of proper quarantining and stressed animals due to poor conditions/overcrowding than anything else.> Thank you. <Your welcome, have a good evening Luke, PF>

Benefits of UV Sterilizers I have a 55 gallon. Are UV Sterilizers worth the money? I found one on Dr. Foster and Smith for $74.99 Will it really cut down on disease and stress? One of my LFS told me to be careful of  'snake oil salesman' What are your thoughts? <In general, since I know nothing about the tank's livestock, yes UV sterilizers are beneficial. Worth the money? Too subjective for me to answer. If you keep a low bioload, properly QT new livestock, practice good husbandry, I would recommend you spend the money elsewhere. Hope this helps, Don> Thanks TGIF Christy

Should He UV? Good afternoon gentlemen, <A gentleman...Hmm- I'll have to think about that one...Scott F. with you today!> I'm TIRED of fish being lost do to not having a QT tank!!!! So I'm buying what's needed to do things RIGHT( like I should have done the first time) So my question is to you fine gentlemen: Should I dish out some more beans and buy a U.V light for some Extra caution? What do you think? THANKS for your time. <Well, UV is a useful tool in aquarium husbandry; it can kill free swimming pathogens if the proper flow rate through a correctly-sized unit is achieved. It's not mandatory in an aquarium, but it is a big help! On the other hand- there is really no substitute for good technique, such as quarantine. If you don't have one already, I'd invest in a simple quarantine tank setup (A 10 or 20 gallon tank, sponge filter/outside power filter, heater). It will more than pay for itself in the fishes that it saves! Then, if you feel that you need it- go for a UV sterilizer...Good luck! Regards, Scott F>

Calcium reactor, UV, Ozone Hi again, <Hello to you, JasonC here...> I have a simple one this time. I am constructing a FOWLR. Will this benefit from having a calcium reactor? <Not especially.> Will the presence of calcium help me grow a more diverse range of "things" on the live rock or in the sand (I plan to have a deep sand bed too). <It would pay to keep the calcium in a decent range, but you could achieve that with additives. Calcium reactors become more useful when you have organisms that consume large amounts of calcium.> Will a UV sterilizer help or hinder a DSB and LR? <Don't think it will affect it either way, but in general more useful for hospital and quarantine tanks.> I want to use ozone, how do I know what size of unit to buy? <Buy what you can afford WITH the controller.> I cant find much on that. I plan to use an ORP controller so that will take care of things for me but I don't want to buy a unit that is too big or small. <Most of the small units available to aquarists are too small to get into big trouble with.> Thanks, Adam L <Cheers, J -- >

UV effects on plankton? 5/20/03 Good morning everyone!! <cheers> I have heard that if you have corals in your aquarium, you shouldn't use a UV sterilizer, because that would eliminate the things that the corals feed on.  Is this a fact???     <a small matter either way. Assuming your tank even produces plankton (few do adequately to feed corals).. the UV will nuke some plankters... yet the dead are still consumed by filter-feeders. Ultimately, though... I see little need for a UV on a display tank... a poor method of disease control (dubious efficacy under practical applications). Ozone would be much better for this purpose and has other benefits> If this is true, then if I were to use a UV sterilizer, and manually feed phytoplankton a couple times a week, would the corals be satisfied??    <agreed> I ask this because I have noticed that UV sterilizers help control unwanted algae. <they certainly do... and very well. Yet, the cause of the algae is excess nutrients. Control the nutrients (aggressive skimming, proper feeding/stocking and water changes, etc), and the UV is still not needed> Pat Marren <kind regards, Anthony>

Putting UV To Work Question about Ich... Do UV filters help in the control/spread of Ich and other pathogens in the water? I heard they do, but just want to know before spending $100 on one of these babies. Thanks much, you guys are great!! <Well, there are some serious benefits to using UV on a continuous basis in your system. They do kill many free-swimming pathogens, among other things. It's possible that they can kill the Cryptocaryon parasite during the free-swimming phase of its life cycle. The key to success with UV is to get one of the proper size for your system, and to run the proper flow rate through the unit to achieve an effective contact time to take advantage of the sterilizer. Good luck with your system! Regards, Scott F>

- UV Sterilizer and Other Questions - Hello WWM, First I would like to thank you so much for all of your hard work on the website. It is first class. I have two questions: <Ok.> I have a 230 gallon FOWLR Marine tank that's water parameters seem to be perfect.  NO ammonia, Nitrite in the last 9 months or so and my PH and DKH are always right on.  My frustration lies with my nitrates.  They have been creeping up lately and now are at 20ppm.  I just did a 55 gallon water change this weekend and it did not seem to help.  How often should I be changing my water and how much? <I like 10% every two weeks, but 5% every week is probably overall the best for any tank if you can stand that much maintenance.> And how would you recommend that I fix this nitrate problem quick? <Depends on your system... do you by any chance have a wet/dry filter?> Also what is an effective level for calcium? <In my opinion between 350 to 400 although many prefer 450ppm. Depends really on maintaining those levels.> I am trying to grow more purple algae. Secondly I have a double helix UV sterilizer (36 watt), in my sump.  Is that enough wattage and should I purchase another? <I don't think UV is worth the time or money on main systems - great for quarantine, but hard to tune for larger systems. The big variable is a low enough flow rate adequate to kill protozoans.> I also am curious if there is a place that I can put it to make sure it is most effective? <Again, careful quarantine procedures can make UV sterilization a waste of time, and likewise there is some anecdotal evidence of an acquired immune problems in systems that have run UV for extended [years] periods of time.> Your help would be greatly appreciated, Matt <Cheers, J -- >

Would You Use a U.V. for This? >To the Wizards of WWM, I love your website! So I thought I'd ask another question. I have a 75 gal tank that has been running for some years now. I've recently upgraded the lighting to a MH/PC combo.  I am now having a terrible problem with algae bloom, on the rocks, substrate and glass.  I never had this problem before with my previous lighting setup, (SO Fluorescents).  Yes, I also have a working skimmer.  I realize that it is probably too many nutrients in the water; even though the algae returns only 2 days after a major water change.  I got the idea to use a DSB with some LR in my sump to help cut down on the nutrients.   >>It's a pretty good idea.  Make it a full-blown refugium and you'll be even better off (for the use of macroalgae through which harvest would garner direct nutrient export). >However, the guy from my LFS, suggested a UV Sterilizer instead. >>Because a U.V. would do what, exactly? >HUH???? >>YEAH! >Should I use the sterilizer instead of the DSB? >>Um.. NO.  They don't have anything to do with each other, one sterilizes (this means kills things), the other GROWS things that utilize and convert certain nutrients. >Would both be effective? >>In their own capacity.. well yes, though I'm not at all a fan of U.V. in home aquaria, ESPECIALLY reef with refugia. >Please help. I'm just about at the end of my rope with this problem.  MiMi >>This guy is.. how do I put this..?  Talking out of the wrong orifice.  He clearly has NO IDEA what the function of a DSB is, nor the function of a U.V. sterilizer.  If there were a stupid law it would say that you may smack him upside the head simply for being so.  Let him not muddle your mind with useless drivel.  Marina

Ultraviolet Sterilizers? I have a 20 gallon long tank.  I want to add a UV sterilizer.  Could you recommend a good UV for this type of tank?  Or do I even need one?<To be honest with you...I would not purchase a UV sterilizer for an aquarium this small. I would make sure that you have a protein skimmer though. Good luck, IanB>

Shortest question of the week: UV use 10/18/03 How do you feel about the use of U.V sterilizer in 75 gallon tank. <ahhh... that depends if it is on freshwater, saltwater or a QT tank? Hmmm... frankly, if you are quarantining all new livestock properly in a QT tank (with UV if you like) before adding them to the display, the UV will not be needed. They are also strict in application (require maintenance of an excellent prefilter and the use of carbon and/or ozone weekly or better for water clarity). Anthony>

To UV Or Not? Hi Scott, how are you doing, hope you're doing great. <I'm doing great! Hope all is well with you...> I just purchase these weekend my protein skimmer, I got the REEF CS6-1 Series, and works like a beauty, but barely fit. <Hey- at least it fits! A great skimmer that will do a wonderful job!> Doing a little research, I wanted to ask your personal opinion on Ultra Violent Sterilizer, are they necessary, do they help a lot, or are only necessary for reef tanks????  Thank you for your advice. Att. Juan <Not necessary, but a nice thing to have. Personally, I think you can get by without UV, but it's your choice! Do some research on the WWM site regarding UV use in reef systems, and you'll be able to make an informed decision! Good luck! Regards, Scott F.>

- Effectiveness of UV Filtration - Are there any scientific data or real life experiences of effectiveness of UV lights in killing Cryptocaryon (marine Ich) spores (free swimming)? <Yes. It's all a factor of bulb wattage and flow rate.> I'm looking to get CSL Double Helix 36W for my 90 gallon. The flow through the sterilizer will be 200gph. Big question: will this dosage be enough to kill free swimming Crypto spores? <You need to ask Custom Sea Life - they should have data on the effectiveness of their bulbs vs. flow rate. They should be able to recommend the correct flow rate to kill protozoans.> Thank you,  Luke <Cheers, J -- >

UV for a Reef (12-15-03) Also, Is a UV beneficial or harmful to a reef environment? I have 57 Watt, and I'm thinking reef?<It's a matter of opinion here, some people run a U.V some don't.  I run a U.V on my reef and have seen no ill effects.  It seems to help with water clarity and algae outbreaks.  I say research and decide for yourself as each person views this in different ways.> Thanks for all your help!<My pleasure! Cody>

- UV Sterilizer Questions - Hey folks, Hope all is well in WetWebMediaLand. <As far as I know.> I need some clarification (har!) on UV Sterilizers. <Ahh... good one.> There seems to be a lot of difference of opinion regarding their use. I've poured over all the information on UV sterilizers on all the various reef-centric boards with regards to their effectiveness on Cryptocaryon irritans (Ich) control in the free-swimming stage. One thing I never saw addressed was "sizing big" when purchasing a UV sterilizer. It seems that a 50 gal aquarium calls for an 8 or 9 watt UV sterilizer. Many people claim you will have better parasite control with UV if you restrict the flow to 50GPH through the unit. While this seems to make sense, I'm wondering if "upsizing" your UV sterilizer would have a similar effect rather than restricting water flow. The difference in cost between a 9 watt and 15 watt is minimal, and the cost to move up to a 25w seems reasonable. <It might 'seem' reasonable, but you should know that a 25 watt UV still needs a flow rate of about 150 GPH to kill protozoans. There is no exponential relationship between the size of the UV and the required flow rate.> I currently run a closed-loop system with a SCWD and Mag unit that's rated at 700GPH. The loop is simple in my 37 gallon Oceanic "Cube". It's basically a Lee siphon tube running to the Mag, then from the Mag to the SCWD, then the SCWD to the outlets. I assume that the flow gets restricted significantly right at the SCWD, particularly when switching. <Actually, no... this item is well engineered and causes no back pressure when switching.> I'm considering picking up a 15w AquaUV unit to place between the Mag and SCWD. Is this the optimal spot? <No. The ideal way is to plumb the sterilizer separately with a dedicated pump in the sump and a return line to the tank.> If restricting the flow through the UV unit makes for a tangible benefit, should I isolate the UV unit with a couple of T barbs and restrict its flow with a ball valve? <This would also work.> Thanks so much for your help. Karl <Cheers, J -- >

UV Questions <Hello! Ryan Bowen with you today> As always, the information on your site is very informative, however I was not able to find an answer to my question this time! <No problem> I know bigger is better, and I have two marine tanks side by side and the water runs between the two tanks (a 110gal and a 55 gal). <Cool> I have two water pumps, that circulate the water back and forth. (Stocking is mild I would think... (Please give your opinion) 110 gal holds; 1 large maroon clown and a med. Atlantic anemone, a med/large finger coral, one electric blue and yellow damsel, one Chromis, 2 cleaner shrimp, one boxing shrimp, 6 turbo snails, 1 brittle star fish, a good size angel (not sure what type, but she eats well and is healthy) and a yellow tang. <Everything sounds good, although the angel could certainly need bigger quarters, depending on type.>  There is about 1 inch of sand on the bottom and about 50-60lbs of L/R with an under gravel filter that runs, not a plenum (sp?), two power heads to run the U/G, a Fluval 304, the custom built-in filter (made for the tank), a SeaClone 150, and a double helix UV filter rated for 150gal. <OK> The  55gal houses a mated pair of Percula clowns, 3 Anthias, 2 3-stripe humbug damsels, 5 hermit crabs, and 5 clear shrimp (they are feeder shrimp who never got eaten! They are now too big to eat but do a good job cleaning, so I left them in.) There is also a Fluval 304 on this tank, a Berlin air-lift 60, an off brand UV filter rated for 100 gal tanks, 2 power heads and an U/G filter. 2in. of sand and about 30lbs L/R. Water parameters are PH-8.2 ammonia-0 nitrites-0 nitrate-0? (test is hard to read the difference between 5 and 0 at least under 5ppmcalcium is 405.) ***My question is this... I have a 25gal bare bottom tank with an Aquapro-1 filter (-British brand? rated for tanks up to 50 gal)<Never heard of it> that I use for my QT tank. When there is no fish living in it, it is connected with the main tanks to help with circulation (so the good bacteria don't die in the filter).<Nice setup> When there is a fish inside, I take off the connecting water pumps. I was wondering if I could keep the quarantine tank in connection with the other tanks if I placed a UV filter between the QT and the 55 gal. when there *IS* a fish in the QT, and only disconnect them should the need arise for medication? Thank you for your time and sorry it took a lot to get the question out! Amanda <Amanda, it seems pretty risky.  The entire idea of a quarantine system is to prevent any possibility that contaminants can proliferate in the display.  If copper medication would ever need to be used, you would not be able to reconnect the QT tank for fear of copper poisoning your invertebrates with leaching.  Good luck! Ryan> UV sterilizer Will a U/V sterilizer help destroy red slime algae since it is a bacteria?<It may help a little but the best thing you could do is get a good quality protein skimmer and keep up on the water changes using RO water.  If you don't already have a UV I would not purchase one for your uses.  Cody> Thanks!

75 Gallon Stocking II Hey again,<Howdy!> I forgot to mention about the tang the ich thing won't be a prob.  I've got a UV.  <UVs are no guarantee against ick, it only is effective when the ick is actually in the water column, which is not for very long.  I would set up a quarantine tank now as they are one of the most important components to being successful.>Is this still a no go due to size?<Yes, they are also very touchy fish.  You can read up about all this some more at our website: www.wetwebmedia.com.  Cody> Akira

UV sterilizers Hi, <Hey there> Need some advice (thanks in advanced). Btw, if you can remember me, I'm the one that seeking your advice about the "free" Snow Flake Eel that come with the live rock. Well, FYI, I manage to trap it and now its at a diff. tank (living happily - I guess). <Ah, good> a) Can I turn on my UV sterilizers for long-term. My tank is with Coral & fishes? (My friend told me that the coral might not "open" anymore because the water quality change --- friendly microbes also get killed) <Should be left on continuously. No worries re killing off too much of the beneficial water-borne microbes> b) If can not turn on for long period, what is the recommendation? <Leave it on> c) I'm suffering for white spot 2 months ago. Most of my fishes died. left only a cleaner shrimp, 4 small fishes. I try to perform a "fallow" but couldn't catch the fishes, however after 6 weeks when I see no sign of white spot I then introduce 1 African Crown, 4 Common Crown, and 2 weeks later all dies due to white spot. Must I remove all fishes? <Yes my friend> d) If I manage to catch all the fishes, Can I leave the cleaner shrimp inside while performing the "fallow"? <Yes> e) Due to the white spot, I purchase a 9W UV Sterilizer. Will this be the BEST solution (against white spot) for me to always turn it on? and perhaps couple with a "quarantine tank system" for new fishes? Or the UV system is already enough? <Quarantine... and possibly dip ALL new fishes. The UV alone will NOT prevent or cure Crypt infestations. Bob Fenner> thanks.  rgds, ws teoh

UV and a refugium Hello WWM. I love your site! my question is simple (or at least short) I bought a U.V sterilizer and I'm using a refugium. Should I use the U.V or not. My tank is cycling. My refugium is full of life tons of Caulerpa and millions of copepods. The U.V defeats the refugium right? Thanks for all the info ..Bill <Actually, the UV and refugium are not mutually exclusive and ultraviolet use should have no discernible negative impact on the refugium. Bob Fenner>

Re: UV and a refugium Thank You! For the response  . That is very cool of you and I feel privileged to receive such valuable information from such experts. let me ask one more. First of all the stats: I have a 90 gallon. drilled tank with a 30 gal (I think, its big) refugium in the basement. I pump it back with a velocity t4 with about 8' head room into a SCWD which splits the flow back and forth from the rear corners at 45s. EV 150 skimmer. a 1/5hp chiller and the 25 watt U.V unit and two Hagen 4000 powerheads (should be enough flow)  Lighting 2 175 MH and 2 110w actinics. ( I'm shooting for the SPS / LPS tank) I looped the skimmer and the chiller and the U.V together. and 90 lbs of Walt smith's Pukani rock (thanks for the advice. it's the nicest rock I have ever seen) soooo my question is on the U.V ,should I leave it all the time or put a timer on it? Does it help the tank cycle? <I would leave the UV on continuously AFTER the tank has cycled> I'm afraid  of it's what it maybe killing good and bad. What do you think? Thank you Bob. I just ordered your  book. ( I cant wait) Your Friend Bill <Know you will enjoy, gain by its reading. Bob Fenner>

- Trigger Ich - Thanks again for your previous response. I check my water quality on a regular basis and it always measures out fine. However my fish keep getting ich. I was told that dropping the salinity down to 1.014 the fish would still live but ich cannot. <This combined with other treatments can help.> I have tried it for about a week now and they are still scratching. I only have two medium sized triggerfish in a large tank. Do you have any suggestions? <Might consider catching them and putting them through a pH and temperature adjusted freshwater dip... and perhaps even leaving them in quarantine for a while and running the tank fallow for six weeks or so.> The tank has been set up for about 2 months now. <That's actually not very long... could be you are having water quality issues which cannot be measured... would step up the water changes and get some other options up and working... for instance quarantine tanks.> What are your thoughts on a U/V sterilizer? <These provide some amount of good, but are not instantaneous cures and typically need low flow rates to actually kill protozoans - slow enough that the sterilizer will take weeks to see all the water in the tank. So yes, it will do you no harm, but no, it probably won't help in the immediate term. Please read here: http://www.wetwebmedia.com/parasiti.htm Cheers, J -- >

UV Sterilizers 7/28/04  Hi--<Hey Janet, MacL here with you tonight>I read your article on UV Sterilizers and still have a few more questions. We have a 175 gal tank with 350lbs of live rock and the following: two false clown perculas, 1 coral beauty, 1 marine Betta, 1 strawberry Pseudochromis, 1 royal Gramma, 1 mandarin dragonet, 1 yellow tang, 1 Bannerfish, 1 harlequin Sweetlips, and 2 female blue devil damsels. I also have a cleaner shrimp and various crabs for clean up. I want to add a hippo tang, since my kids are so keen on having "Dory" from the Nemo movie. I know they are prone to ick, and the other day at a fish dealer I ran into a man who runs a business maintaining saltwater aquariums. He strongly recommends a 5 - 7Watt UV Sterilizer, especially if I'm going to get a Hippo Tang.<Actually in my experience I would add more cleaner shrimps and that should take care of the problem with ich.>  Will this kill off the pods in the tank and do you think it's a good idea? <What a UV kills depends on the speed of the water going through the UV filter. Whether it be algae or bacteria, etc.> If so, how often should it be running? Speaking of ick, I see one white speck on the strawberry. I can't tell if it's ick or not, because there are small white particles swirling around the tank, at least some of which look like pods. It's hard to tell because the power heads keep the water moving. Should I attempt to catch the strawberry and toss him in the QT? <If you only see one dot then just keep a close eye on him. The cleaner shrimp should take care of it. Cleaners are marvelous creatures.>  I hate to stress the whole tank if it's just a speck, and not ick. I've had a false alarm before. Would a UV sterilizer kill and ick in the tank? <Depending on the speed of water going through it, it will kill ich.> Thanks, as always! R/Janet

Using UV for quarantine Hi!! I tried to use a different approach to quarantine for my new fish additions. I set up a 5 gallons QT with a huge Eheim canister with plenty of bio-media, carbon, Chemipure and nitrate remover so I can keep the water quality at its best. << 5 gallons is pretty small. >> It really works perfect, even with such a heavy bioload as two very small ocellaris, a Salarias fasciatus, a small blue Chromis and a 2 inches Zebrasoma flavescent. Also I kept about 3 pounds of live rock with some Actinodiscus. For keeping parasites and bacteria in check, I installed the biggest UV sterilizer I could find: a 24 inches, 36 watt one running 250 gallons per hour irradiating 90.000 uw sec/cm2, what is twice the required for killing the ich swimming larvae. You see, nearly every minute a volume of water equal to the whole system (11 gallons) pass through the UV. I expected this overkill method would be enough to exterminate this nasty disease without the need of chemicals but... NO! Doesn't work. Even adding a pump so all the water goes to UV every 30 second still the ich has time to find a host INSIDE the aquarium. I had to go back to the copper, something that I don't like at all because the brand that I use (Sea Cure) make my fish to look miserable and I always have to take some losses no matter how carefully I monitor the concentration. I don't know if there is any flaw in my idea, but I wanted to share my experience with it. << Thanks for sharing, I'm sure it will help others. >> Thanks you all for your wonderful and generous work. << Thinking the UV may still be a good idea, it just may need other treatments to go along with it. >> Cheers! <<  Blundell  >>

UV recommendations 12/27/04 Hi, this is Jonathan. I have recently purchased a UV Sterilizer for my 125gal tank. I have been getting a lot of opinions about if UV kills or does not kill all the needed algae and beneficial bacteria. <UV kills whatever passes by it.  The rate of kill depends on the wattage and age of the lamp, the water flow through the unit, how clean the unit is, the specific organism in question and more.  Some beneficial life will be killed, but since most of the "good guys" are most abundant on surfaces, the UV will not make a significant dent in their populations.> I was just wondering because my tank is still developing, and I would still like to get some more hair algae and have for when I get a Hippo Tang. I also was wondering if that it's not so much the wattage but how fast or slow the water moves through the UV. <Hippo tangs are among the least herbivorous tangs and will eat very little hair algae.  The kill rate through a UV is dependent on both flow rate and wattage.  At very slow flow rates, even a small unit will have a high kill rate, but so little water will be processed that the unit will be ineffective.  The other extreme is a high wattage unit with very high water flow.... lots of water will be processed, but the organisms will pass by so quickly that the kill rate will be too low to be effective.  Hope this helps.  AdamC.>

Re: UV or not UV? That's a reef question Thanks for your reply. The reason I asked is that in the book you suggested that a UV unit might result in an immune problem and kill good necessary microbes as well as the bad ones. My wife bought me a UV unit for Christmas, and I'm am trying to figure out if I should use it on my 50 gal reef. If so, should I run it less than 7/24? Does using this unit reduce the risks associated with using free Scripps (SIO) water. Thanks again. >> I would use a UV if I had one on any given reef system... And yes to reducing the chance of introducing undesirable microbes from the raw (but sand filtered and free) water from Scripps Pier... I would still store it in the dark, circulated for a week or so before use. Bob Fenner

In a nutshell, are UVs beneficial or not, or not much?  I have read so many opinions one way and the other - can you comment? Thank you for your answers - your column is a wonderful resource. Urey Patrick >> UV's are beneficial,,, for killing much of the in-water microbe population, raising dissolved oxygen and reduction oxidation potential >> Oh, and stop touching those buttons too soon: Let's see, where was I? Oh yeah. UV's are of use, but how much? A few to several percent improvement in disease prevention and water quality improvement. Is this "worth it"? IMO, only after other aspects of water quality have been looked after. Biological filtration, mechanical, skimming, even ozonation and a dryer are more important... Bob Fenner Preventing Parasites with a UV? Nope Hi Bob ! I have a 55 gallon reef/fish setup. In order to help prevent parasite outbreaks I would like to hook up a UV sterilizer IM a little confused on the size to get and do you recommend one? Thank you.  Richard Tarr >> Hmmm, well let's see. First off, I would like to (so I will) state that such a contrivance will not prevent parasite outbreaks... but it will help to do so. I would definitely run your new livestock through dip/bath and quarantine procedures in addition... and this should do about as much as you can prophylactically... Now, the "size" of UV is a function not only of your size system, but also of the mechanism used to run water through the "contact chamber" for an effective "kill ratio" per pass... you understand? But about 20-25watts is what you're looking for... place the UV in line with part/all of your circulation/filtration gear as the last item before the water is returned to the main/display tank. Bob Fenner

UV FOR Reefs Bob, I have a 120 gal reef system. live rock/sand/skimmers. Will UV kill the nitrifying bacteria, etc that a natural system needs to continue the ecosystem?? Do you recommend the UV? Wayne >> Hey Wayne, thanks for writing. No, the UV won't kill off your nitrifying bacteria. Most of these are situated/attached to hard substrates, and the UV's only zap what passes by them in the water column. Yes, I do recommend UV's, they do a great deal of good besides reducing overall free-living microbial populations: higher dissolved oxygen, reduction oxidation potential.... Better water quality over all. But they are not the most important piece of reef-keeping gear for hobbyists IMO. Way before you should have good filtration and circulation... Bob Fenner

Great Book! UV, Crypt Bob: I had to get out of the marine aquaria hobby about ten years ago, and have been itching to get back into it ever since. I picked up a copy of your "Conscientious Marine Aquarist" earlier in the year, and have thoroughly enjoyed it. I have found it to be extremely comprehensive on subject matter. Of course, the color pictures are fabulous, and I especially enjoyed the chapters on various species in the second half of the book. It was the catalyst I needed to get back into the hobby! I've also found it to debunk some bad advice I've been given at a few aquarium shops. I set up a 75 gallon tank back in about June, and currently have ten fish. However, I seem to have a persistent ich problem that cropped up a couple of months ago. I have a 10 gallon quarantine tank, and of course, could not remove all my fish to that tank for treatment. Consequently, I had to add copper to my main tank. I added Coppersafe, and maintained the level between 2.0 and 2.5 ppm for about six weeks. The problem seemed to subside, and afterward, with water changes and activated carbon the level dropped to 1.5, and then symptoms reappeared. I added more Coppersafe, but lost a Double-Saddle Butterfly before the added medication started to take effect. Am I forced to permanently run copper in my system, since I can't remove all my fish to my small quarantine tank while I "sterilize" my main tank. I've been told that ionic copper is more effective than chelated (Coppersafe). However, the instructions on the ionic copper state that it should not be used with any chelated copper in the system. Anyhow, I'd never be able to tell how much ionic copper is in the system as long as there's some chelated copper in it. Any suggestions? I suspect you're probably very busy, so if you can't respond, I understand. I mainly wanted to tell you how much I've enjoyed your book! >> Thank you for writing, welcome back to the fold (the marine hobby), and I always have time for (high praise and) offering my help.  I hear you on the dangers of constant copper use... and the mixing of chelated and non-chelated forms.... Don't do it! Or at least (for browsers, but not in your case), remove the "old" copper first with activated carbon... Now, what I would do in your case: Unless you have a big, mean fish like a trigger that will munch them down in a sec., get a couple (two) of the following: Lysmata Shrimp (amboinensis) and Gobiosoma gobies... Not to worry if these species don't occur in even the same ocean as your other livestock. With low grade, consistent infestations as yours, these facultative cleaners are just the thing to tip the balance in your fishes (and your) favor. Bob Fenner

I am considering purchasing a UV sterilizer to kill the parasites on my fish and then prevent them from coming back again in my new 75 gallon aquarium. I have heard that having the correct flow rate is necessary. What flow rate would you recommend. The UV I am considering to buy has a 25 watt bulb and a 3inch diameter and is 17inches long. >> Don't mis-invest your time and money. A ultraviolet sterilizer will not, repeat NOT kill parasites on your fishes... it will kill some water-borne micro-organisms and aid in producing higher quality water conditions... but you should first put your money and efforts into preventing the introduction of parasites, infectious disease agents and weak new livestock, by purchasing, setting up and operating a quarantine/hospital tank for all new livestock... take a look at the articles on disease, quarantine on the wetwebmedia.com site... Yes, UV's can be worthwhile, yes dwell time is important, yes, some brands are much better than others (I like the Tropical Marine Centre line best, for reasons I list in articles at the site listed)... Read on. Bob Fenner

UV sterilizer sizing I was just wondering about your opinion on UV sterilizers. I have a 75 gallon tank, mostly fish but a few corals. What size would I need and do I run it all day, 7 days a week? I didn't know if this would take out all the nutrients for the corals. Do the sterilizers really help with disease prevention? I lost a cow fish and brown tang just yesterday from what initially appeared to be ick. It seems that only a small few of my new purchases survive, but my established fish seem to do well. Thank you for any help in this matter. >> Hmm, yes, Ultraviolet Sterilizers are useful adjuncts (additions) to otherwise well set-up, filtered and maintained systems... They do enhance water quality, increase dissolved oxygen concentrations, lower the incidence and virulence of water-borne infectious and parasitic diseases... Now, as to size, this really should be matched with the flow rate of whatever pump source you're going to use... Makes sense to not "overpower" the given rate of flow that you can zap to near a 100% kill per pass... so match the flow rate with the dwell time... All real manufacturers will give a standard linked to gallons per hour... flow rate. And, nah to the UV extracting nutrients from the water... negligible effect. But, hmm to your persistent losses problem... might want to review your selection practices... dipping/quarantining/hardening routine... and possibly consider some biological cleaners... You either have poor fish from the get go (try another dealer), an anomalous condition in your tank (like overdosing history from supplements, or a toxic blend of salts from something like removing the crust from your top...) or a biological condition that your extant fishes have adapted to, but is too much for new ones... Bob Fenner

UV Sterilizer, help with Crypt... some Hello, I have another dreaded ick question. I am considering purchasing a UV Sterilizer for my FOWLR tank. It is 120 gallons with wet/dry, and a protein skimmer. I was interested in knowing in your opinion do the sterilizer really help eliminate the ick infestation. Is there any particular brand that you can recommend? Lastly, if there are no visible signs (i.e., white spots) on the fish does it necessarily mean that the fish is not infected? I know it's possible for the parasite to be in the gills. But, wouldn't there be a sign of heavy breathing? Thanks once again for your enlightened help. Tanya >> An ultraviolet sterilizer does/will help to control ich (and other water-borne) diseases... through improved water quality as well as "zapping" parasites... But it will not generally cure an existing problem, nor totally disallow their possibility. Careful selection, handling, acclimation, dips/baths and quarantine are just as important in avoiding and curing these problems. The UV units made by Tropic Marine Centre are superlative... There are residual infestations of ich that can/do come from "resting stages"... Though most of these do not "originate" on their ultimate host fish(es). Put another (hopefully clearer) way, there are specific pathogen-free fish livestock collections, where ich has been excluded from a system where marine ich won't just "pop up"... unlike freshwater "ich" of the same name, different holociliate protozoan cause. Bob Fenner

UV sterilizer... too much? Hello again. Does a UV sterilizer get rid of anything from the water that the fish need? Is it good to let it run all of the time? <Nothing that's ultra-important... do leave it running continuously>  Also, I have hung my UV sterilizer on my wet-dry filter instead of on the tank itself. Will this kill something that the wet-dry needs in it? <No, but it might be more useful to place it returning to the main tank... to reduce the incidence of bubbles going through it (cuts the efficiency), and will give you the most kill per total passes, improved water quality...> Thanks for your help. Chris A. Johnson <You're welcome. Bob Fenner>

UV, other gear choices well here we go again. want to spend more money. ozone or UV sterilizer. LFS says i will need pump, dryer, and carbon filtration for ozone. <Depends on where you place the ozonizer... a pump is unnecessary if you can rig up the discharge on the intake of a "venturi" intake in your system... like the air intake for your skimmer... And a dryer/desiccator? Not essential even in relatively moist environments... unless you prize the greater efficiency from drying the air before it goes into the ozonizer... even then you can make one inexpensively...> although i can get several options (ORP, etc), it seems considerably more expensive than a UV sterilizer.  <Well, one of the chief benefits of working Ultraviolet Sterilizers is their production of... ozone... but the ozonizer does produce more...> is it that much more efficient? we are also in the process of adding a sump with Berlin skimmer with Rio 2100 and Rio 2500 for return. you know it is a shame that LFS don't spend more time with us newbies. if i had gotten all of this new stuff on the front end, i wouldn't be stuck with a canister filter, undersized skimmer, undersized exterior filter and god knows what else. well what do you think, UV or ozone? thanks Jim nix  <For your system, a UV... for now. Bob Fenner>

To UV or not to UV? Hi Bob, Thanks so much for getting back to me. I actually did that while waiting your reply. The water is now green!!! ARRR!!!! Why is this happening? I have  also limited my lighting time to 3-4 hours a day. Would using a UV Sterilizer help? Thanks so much again.Brian  >> System is "out of balance"... more light and somethings to use it would help more than a UV... live rock, macroalgae... in a sump, or the main system. Bob Fenner

UVs, Ozone, Stocking Questions First, I would like to say YOU'RE THE MAN. I have 180gal FOWLR tank, which includes: 150lbs. Of LR 5 inch Dragon Wrasse Turboflotor 1000 5 inch Red Sea Lunar Wrasse 30 gal sump 4 inch Blue Throat Trigger  25 watt UV 12" Snowflake Eel FB600 Sandbed 50-Micron bags used for Mechanical Filtration Mak 4 pump I was wondering after already using your dip techniques describe at the www.WetWebMedia.com site is almost useless to have a UV Sterilizer hooked up to the tank. <Has nothing to do with UV use'¦ UV's are useful adjuncts to improved water quality and hence health of livestock. Quarantine is a useful technique for eliminating infectious and parasitic disease, assuring the readiness of introducing new livestock, healing weak specimens'¦> I know that it helps improve the water quality but is it really worth the up keep.  <Depends'¦ is the few percent improvement worth it to you?> The guys at Custom Aquatic told me that I should replace the bulb once a year and clean the sleeve every month. <Yes, good general rules of thumb. The manufacturer of the unit will give more> Changing that bulb can cost after a while at that rate. <Less than the electricity to run it 24h/d'¦ or perhaps the money, hassle, heart break to replace your livestock> I also read your book (The Conscientious marine Aquarist) and it seems that you prefer the use of an ozonizer.  <Yes, IMO, better than a UV'¦ but both are worthwhile> Well in reading different things at wetwebmedia I could never find anything discussing of the right size to use on various sizes of tanks. Could you help me out here? Which one of these techniques would work better for me? In addition, I can't find the DIY UV on Wetwebmedia.  <Hmm, the size of? UV's has a bit to do with their design, effective flow rates'¦ but a twenty, thirty watt unit will get you about all you're going to get for this size, type system '¦ no need to shoot for some near one hundred percent kill rate per pass'¦ or seek to raise redox, dissolved oxygen through this means> Right now, my tank utilizes the Mak 4 pump for water circulation and I was thinking about upgrading to a Dolphin 1200gph silent series, but Am not sure, if I want to spend the money for their quietness. <Up to you.> I recently placed a small Rio pump in the tank and the fish kinda took turns swimming in its flow path (that was funny to watch). I noticed that with many different dealers in my area that they have the water inlets set-up different. Some have the inlets pointing down at an angle in the tank and others have them the top of the tank causing a ripple effect. Is there a right way into doing this?  <A little to lot of both> Am assuming if I had the inlets pointing downward into the tank that I could achieve greater circulation and a uniform temperature throughout the tank. In addition, I was thinking of adding to smaller pumps near the surface to push water toward he overflows. What do you think about adding more water flow into FOWLR tanks? Should it be just as half as much as reef tanks? <The more the better for all> My last question concerns stocking. I would like to add a 4" Gray or French angel, 6" Naso Tang, and a 4" Red Spotted Hawkfish to my tank. These would be my last additions. Would this be over crowding? <No, but these would be more than capacity with growth'¦ Okay for a year or so. Bob Fenner>

UV sterilization and beneficial bacteria Hello Robert, I have recently been given some live rock that was left out of water for an extended period of time. So, what I am left with is some very nice pieces of porous once live rock. <Okay> I know that beneficial bacteria and algae will colonize other suitable objects when placed in an environment where they already exist on or in other objects, like live rock, but what effect does the presence of a UV sterilizer have on this process?  <As in the water in the system passing by way of UV radiation? Negligible effect> Is the beneficial bacteria and algae able to colonize the new objects or are they trapped in the existing live rock and sand, zapped once they become water born leaving the non-inhabited newly introduced pieces of once live rock fallow? As always thanks Steve B. <All a sort of percentage game... but more than enough micro-life will get around to quickly colonize/recolonize this material. No worries. Bob Fenner>

Re: confused-urgent ick problem Dear Bob, When we put the little Naso back in his home tank, he continued to look better and the next morning his dark spots were barely there. He still looks good. We called all over town and found a few cleaner shrimps. I wanted them anyway and I hope they can avoid becoming an expensive lunch for the hermits.  <Yes, they should be able to co-exist... unless you have "mean" species of Hermits... and/or both are hungry...> I love that little Naso (not so little). He's amazingly intelligent. I hand fed him Sunday as much as he would not spit out while he was in the copper tank. Now he eats out of my hand reliably. After yesterday, though, he turns distress colors when he sees the net. I hope I can win his trust back. <You will> Thanks for all the replies. People tell us getting a UV filter will prevent this.  <No... a myth> Now I'm just hoping the shrimp and fish "bond". By the way, your web site is an excellent source of info. (I would expect nothing less given that your book was so wonderful). <Ahh, thank you> I can't help it. I love this fish. Thanks again, Allyson <Be chatting my friend. Bob Fenner> Allyson C. Rosen, Ph.D.

Ich, marines, questions Mr. Fenner, I have not bothered  <Never a bother my friend> you in a while, but I have a question regarding an ICK problem. I have a TMC Vecton 8 Watt UV sterilizer, <My fave consumer line of ultraviolet sterilizers.> protein skimmer, 45 lbs of live rock and a penguin power filter on a 30 gal tank. Water parameters are for the most part perfect, and the temp never fluctuates more than one degrees from 77. I have a 65 gallon tank waiting to be set up, but you told me not to transfer the fish until the ick problem has been solved, and at this time I don't have the resources to set that tank up for a while. Well here is my question, Am debating whether to treat the actual tank. The main concern of the ick is on a yellow tang. This is my second yellow tang, I figured with the TMC unit in that the Ick problem would be greatly reduced. <A few tens of percent. Is that greatly?> Two other fish that had ick since putting in the UV sterilizer no longer show signs of the ick, but the tang for some reason, even with the UV is still getting ick. For the first week I ran the UV for 24 hours a day, but now I have switched to 8 hours of UV sterilization (How long should the UV be running?).  <Continuously... All the time. Please read: http://wetwebmedia.com/marphysf.htm> Even when the UV was running 24 hours a day , the tang still contracted ICK. I have done 2 freshwater dips on the little guy, but within 5 days of being put back in the tank, he contracts the ick. <Yes, the ich is in your tank... not just on the fish. Please read: http://wetwebmedia.com/parasittksfaqs.htm> The first time i did the freshwater dip, I put him in a separate tiny little quarantine tank for like 5 days, but once he was back in the main tank the problem returned. The problem is every time I have to get the tang out it is a 2 hour ordeal. What are your thoughts of treating the actual tank, <They are posted on our site (WetWebMedia)> i cannot remove the fish and let the tank go empty for a month or two like you recommend because of time constraints and i have no place to set up a temporary tank. I have two corrals currently in the tank, a small brain and a sunflower, but am worried because every magazine i have ever read says not to treat the main tank. <Keep reading> Majority of the ick medicines say REEF SAFE, but how reliable is that statement, do you know of any ick treatment that would not effect or damage the reef tank if directly treated.  <No, they don't exist... the "newer" ich remedies I know of are simple poisons... proteinaceous precipitants by action... they poison the fish host, making it produce more body (et. al) mucus, coating, sloughing off the external parasites... > What do you recommend, I know it sounds funny, but I really want to save the little tang, contrary to what every one is telling me to forget about him and remove him. The tang is the life of my tank. Well thanks for all your great help, and sorry that the email is so long. <No problem with the bother... do read over all the materials on marine parasitic disease including the many, too many FAQs that give glimpses of others trials/experiences.> Why is it the most colorful and enjoyable fish are the most problematic!!!! Alfredo <A corollary of someone's reductionistic "rules", no doubt. Bob Fenner> Thanks once again for your great advice and guidance.

UV sterilizer and a start up reef tank Hi, You have such great insight and were able to help me before. My question is probably more for reassurance. I have a 55 gallon tank, with 40 lbs. of live rock and live sand. I have an Ecosystem 40 mud filter with Caulerpa in it. I have one small sailfin tang and 1 dragon goby. My tank is 3 months old and I believe is in good filtration mode. My current water values are temp. 78, Salinity 1.023, NH3 0, NO2 0, NO3 0, pH 8.3, kH 10-11, Ca 450ish. <Great> I had a huge algae bloom which then turned my water green. The maker of my filter said it was phytoplankton and suggested I use a UV sterilizer. I put the UV on and in 1 day noticed dramatic improvement. Since my trigger died, I thought it was a good time to try my ultimate goal-reef. I have been doing a lot of research and asking around. The marine stores in Missouri are limited. My questions I guess are with the UV filter, if it runs all the time, will it not kill all the algae that the inverts/herbivores may want?  <No, no worries. Will reduce the amount of water-suspended life that passes by/through the UV itself... otherwise improve water quality overall.> I did read a lot of your UV information in relation to immunity. Should I put my tank on a UV schedule, only putting it on so long, so often? <No. Better, best to leave the UV operating continuously> I have power head in the tank for water movement and my lights are florescent 110w VHO. Starter inverts: mushrooms and polyps?  <Good choices> Anything else? What other fish would you choose?  <Huge possibilities... please read through the WWM site here> Can inverts cause a 'recycling' if too many are added at once?  <Yes, but very unlikely> Otherwise what is the recommended light times? And beside Ca and Iodine supplement, what other things should be done?  <Items discussed on the WWM site> And, this may be stupid, but can you touch them or will it hurt them/you?  <Usually good to keep touching to a minimum... almost none that are harmful to humans, but you should wash/rinse your hands ahead and after being in the tank, handling specimens.> Do you use a net?  <Depends on species, usually not...> Do you just place them on the rock? Sorry. Thank you for your time and in advance for your response. <Once again, depends on what organisms you're talking about. Study, chat until you feel comfortable about specific organisms. Bob Fenner> Christine

Copepods and UV Sterilizers Hi, Will running a UV sterilizer kill beneficial copepods and amphipods? <If it is powerful enough, the flow rate through it long (time-wise) enough, yes> I had a large bug explosion a few months ago so I got a dragonet and he was eating like crazy. Now, he still looks like he's constantly picking through the rock and sand, but he is getting skinny as if he can't find enough to eat. I'm thinking about setting up a refugium under the tank and getting a amphipod breeding mat and starter culture from Indo-Pacific, but want to find out why the visible bugs are gone? (Still see larger bugs from time to time.) <Likely consumed by the Mandarin/Dragonet... they can/really mow through such fauna. I do agree, urge you to go ahead with your added sump/refugium plans. Many benefits, much fun. Bob Fenner> Thanks for your time, Michael

Ozonizer or UV sterilizer? Hello again! <Salute! Anthony Calfo in your service again> This time I need your advice about the next step I should make in order to be more "conscientious" (I got Bob's book just yesterday - ordered it from Amazon.co.uk). As you can suppose, I have neither an ozonizer nor a UV lamp. <not necessary but sometimes quite helpful> My marine aquarium is 210 liters (approx. 55 gallons) and is fish-only (for the time being!). I have an Eheim external biological filter (not a wet-dry one) and an Eheim internal sponge filter (I replace the sponge with the Eheim activated carbon for two days a month - is it ok?) , <you certainly can treat with carbon for a longer period of time, even full-time for optimum water clarity> a two-way internal protein skimmer  <do adjust so that it can produce dark skimmate daily> and an electrical circulator. I used to have an undergravel filter but I was told that it makes no sense to keep it since I have an external biological filter, so I took it out. Ammonia is 0.0, Nitrite is 0.0 and Nitrate is 100 mg/lit (maximum of the Tetra test kit!). My Blue Tang has already been through twice a fungus disease and once Amyloodinium. I am told that the installation of a device will help to avoid some of the diseases... What will be my best choice to start with? I have been told that for a small system like mine the best is to get a UV-lamp.  <definately safer, although not a guarantee to prevent diseases. For that, a quarantine tank for all new fish or occasional sick fish would be better> Some of them are fix - their lamps are not replaceable (I have been told).  <if so please avoid these models> Which one should I buy? Is the Tetra UV lamp reliable and good quality?  <a good reputation/brand. Do be sure to buy a model with a quartz sleeve for easy to replace bulbs.> Which size?  <in American wattage, a 15-25 watt unit for your tank> I really do not know. May be too many questions (sorry!) <no worries at all, my friend. Anthony Calfo>  Best regards, Thanassis (your Greek friend)

REDOX, O3, & U.V. Bob,  I was curious if you could point me in the direction of a source regarding the output of O3 from a U.V. sterilizer in closed systems? I know the amounts would be trace but I'm curious as to its over all effect on REDOX and dissolved oxygen.  <Wish I did have a ready source or lead here. Both redox and D.O. are improved by U.V. ozone generation... and the amounts of O3 produced by some U.V. units are appreciable. I would contact the actual manufacturers of the units (a few links on the WetWebMedia.com Marine Links, General Links pages) and ask them in turn if they could provide you with references. Alternatively you might run on over to a large college library, ask someone to help show you how to do a computer search (in the science, technology library/section) as: http://www.wetwebmedia.com/litsrchart.htm Lastly, you might well want to do your own experiments here... using different samples of water, times, turning the U.V. on/off, measuring the values you're interested in. Bob Fenner>

Why won't my UV kill Ich? My entire tank (except for two, maroon clown and wrasse) has ich. I've started using formalin and fresh water dips last night. I've turned the skimmer off but have left the UV sterilizer running. . . is this the right thing to do?  <excellent and just short of perfect without moving everyone into a bare bottomed QT tank> I've considered using Greenex or copper along with the formalin -- do you recommend this?  <rather hostile.. only if necessary. The formalin should be enough> If caught early enough (they are still acting fine, eating good) is ich curable?  <yes... very much so. Can be cured without medication actually with fish in a bare bottom QT tank and faithful daily water changes from the bottom for 8 consecutive days to siphon out tomites of parasite and break its life cycle> Should I still feed them every day, including vitamins? <very important!> I don't understand how I can still get ich -- that's what I bought this UV sterilizer for. . .can you provide an opinion?  <UV sterilizers do a terrible job of preventing Ich. You money would have been much better spent (and less of it) on a hospital tank that all new fish go through first. These quarantine tanks (QT) prevent Ich from entering your display through faithful screening and treatment. ***The problem with a UV sterilizer for controlling pathogens is that they have a narrow range that they will work in. The UV lamp must be less than 6 months old, the water MUST be prefiltered of all particulate matter (sediment free), the tank water MUST be crystal clear (heavy frequent use of carbon else discolorants reduce efficacy of UV light), the UV chamber must be frequently cleaned of sediment and organic slime buildup inside or light is blocked (just look at how much slime builds on power filter tuber in one month), the water flow must be rather slow as per mfg rating for kill time and the bulb must be sufficiently intense to handle the rate of turnover for the tank. And even after all of those things have been satisfied, it can only denature the parasites that are run through it... some may travel through the water and attach to fish without ever traveling through the UV! For disease control Ozone is easier, much more effective but easier to abuse. My vote is always for a QT tank for all new and sick fish> Is the sterilizer helping at all?  <I doubt it if you weren't advised of the above and stay on top of it> Also, my water quality is excellent, I haven't added any new fish in two months, and there have been no changes (new rock added, etc.) to the tank. . . what caused this ich??? <temperature changes are the most common reason (drops or fluctuations between night and day). Very common in spring and fall seasons when house temps fluctuate with seasonal swings and doors and windows opening and closing> Thanks for your help. . .I'm trying not to get too frustrated but this hobby is TOUGH sometimes!!! :) <your just not drinking enough <wink>. Anthony>

Ich solution Dear Bob, Guess that I would like to share my experience. I've went through 3 bouts of ich problem throughout the whole of last year and lost the whole batch my prized angels and BF's. Water changes, medication and whatever nots did not help. My friends suggested copper, not possible as I've got LR and Soft corals. I did not consider UV as many friends claim it does not work and problems in cleaning the plastic sleeve periodically. About 4 months ago, I noticed that my LFS store installed fluorescent fixtures in the sump with special UV germicidal bulbs. I was cynical at first as I always thought that the water has to be within a few mm away from the bulb for it to work. In this case, the distance was more than 8 inches! For the next 10 days or so, I noticed a marked improvement in the loss of new arrivals and also reduction in algae formation on the glass. I've no choice but to try this method. To this date, almost 3 months now, my angels are still alive and kicking and no sign of ich. The bulb I use is only a 18W Philips TUV FL (in the sump )or an equivalent that is Sankyo Denki. Please note that both bulbs are rated as germicidal and do not look too long into the lighted bulb as it may cause blindness. <Yes> My tank is a 200G and for the first few days, it was switched on for 24 hours. Now, I leave it for 12 hours only.. I have no explanation to this but who cares, it worked for me and I would like to share it. <Thank you for this. Will post for others edification, consideration. Bob Fenner>

UV Sterilizers Thank you for your prompt response to my earlier question. Do you recommend Custom Sea Life or Aqua Ultra Violet UV Sterilizers? <I do not really recommend any UV's. Far cheaper and more effective to focus on excellent husbandry. If you want, ask around the various chat forum, message boards, or local aquarium societies for recommendations for your fellow hobbyists. -Steven Pro>

U.V. sterilizer addition value You guys have helped answer lots of other questions, so I hope you don't mind another. I've been thinking about adding a UV sterilizer, but I'm not sure it's worth it. I have a 55 gallon, with 3 inches of sand/crushed coral, a few hardy fish (some damsels, algae blenny, red Coris wrasse), about 12 pounds of live rock (I know not nearly enough, but will increase as soon as I upgrade to sufficient lighting), and a few inverts. No live corals. I've had some ich problems in the past (all is good at the moment), but I'm still almost afraid to add new fish. I've read many of the articles on the site regarding both ich, and UV sterilizers and I see that UV sterilizers are certainly not a guaranteed means of killing parasites, especially in tanks with a sand substrate.  For new tank additions I'm thinking of permanently setting up a basic 10 or 20 gallon quarantine tank with no substrate and a simple whisper power filter... <A much better investment> ...and maybe keeping a fish or two in that simply to cycle and keep the biological system running. If I use that setup as a quarantine, am I wasting my time with a UV sterilizer? <Mmm, not wasting, but U.V. is not a cure all...> I do see that free floating algae is killed off relatively easily with a sterilizer, and was thinking I should get one for that purpose, but I don't want to spend $100 or more just for that. <Plus the electricity to run continuously, replacement lamps...> Are the cheaper ones (I can get, for example, a 9 watt or 13 watt Jebo ) sufficient for that purpose, and will they help at all to control parasites, assuming the flow rate is proper (I understand it should be roughly 20 gph per watt)?  <Small wattages, slow flow rates... will only help marginally> Finally (am I pushing my luck?), the tank is up and running about a year, with wet/dry trickle filter and a faulty protein skimmer (I'm likely to add the AquaC Remora soon). <And this would be a MUCH better investment> Water quality is good, but the water is not crystal clear. Would I benefit from removing some or all of the bio balls at this point and adding a significant amount of carbon in place of the bio balls? <Possibly> Or would I be better off leaving as is and adding a small canister filter, like a Fluval 304? Thanks in advance.  Best Marine Aquarist advice anywhere! <Many things to consider... if it were me, knowing from here what little I do about you, your system... I would invest in a quarantine set-up number one... upgrade your skimmer secondly, and if you have/had more money to put into your tank, lastly of these three considerations invest in an ultraviolet sterilizer. Bob Fenner>

Protein Skimming, Ozone, and UV Use in Marine Filtration 7/5/05 Hello Bob, I enjoyed your article on ozonizers on www.about.com. <Actually on WWM... a link on about.com> I have a quick question for you and don't want to take too much of your time but I would appreciate your opinion. I have a 240 gallon reef with a large population of SPS and LPS corals. With the introduction of ozone to have my protein skimmer at its peak efficiency would be great. But would the introduction of ozone into the contact chamber of the skimmer kill even the beneficial microbes along with zapping bacteria, microbes and unwanted organics? <Oxidizes all indiscriminately. What most folks shoot for is "enough" O3 to reduce free-living bacteria (most ones you want are not suspended in water) and organics...> You stated in the section where you discussed the cons of using a UV Sterilizer that one of the cons of using a UV sterilizer is that you also zap beneficial microbes as well as bad. <Yes... to some extent> In a reef aquarium my corals rely on a lot of the plankton and microbes for food. Would the ozone affect this and is there any recommendations you can suggest on the usage of ozone? I look forward to your advice. Thank you, John Vu <In practical application John, folks have little lingering ozone... providing a few hundred milligrams per hour, delivered to/through your skimmer directly or not, will not harm your livestock. Bob Fenner>

UV Question 7/17/05 Hi, I have a quick question of what you think about the comparison between RO, DI, and UV sterilized water for a saltwater tank.  I know that RO is the best for any saltwater aquarium but I was wondering how RO or DI compares to UV sterilized water? <... compares in what way? Ultraviolet sterilization of water of poor water quality will do nothing to improve it> Also we have well water and a UV light attached to the well (not the aquarium) already, and I know both the positives and negatives of having a UV on an aquarium and I was wondering what you think of have a UV light sterilizing the water before it goes into the aquarium? <... of dubious value... the addition of salt mix to water that has some biological addition will likely kill off most all microbes> (Will this help at all with preventing any algae problems) Thanks for all of you help! <Will do nothing to change the potential for algae growth. Reverse osmosis, deionization are techniques that remove dissolved solids, gasses themselves... You might read re all three... on WWM. Bob Fenner>

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