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FAQs about Ultraviolet Sterilizer Operation/Maintenance

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Getting a little dim in here: Caulerpa racemosa and a few other green algae in the wild.


I have recently bought a second hand V2 400 UV steriliser, the guy I bought it from stated that he use to have it on a six hour cycle: is this a good thing or should it be on all the time? I have a 350 Trigon tank with sump with about 10 fish two of them being tangs (regal and yellow). There is no sign of any disease, I was hoping you could advise me on this.




Ahh, I am a big fan of the Vectron line of Ultraviolet Sterilisers by Tropic Marine Centre... And though some folks do endorse using these... indeed all sorts of gear, like protein skimmers, ozonisers... on a punctuated basis, it is really best to leave them on continuously... For all the "things" that UVs can do... Decreasing overall water-borne microscopic life populations, increasing dissolved oxygen, increasing RedOx potential... About the only times I would shut off your UV is when you are servicing it, or using chemical treatments (e.g. Copper compounds) that the ionizing radiation will mal-affect.  Cheers, BobF


I have recently bought a second hand V2 400 UV steriliser, the guy I bought it from stated that he use to have it on a six hour cycle: is this a good thing or should it be on all the time? I have a 350 Trigon tank with sump with about 10 fish two of them being tangs (regal and yellow). There is no sign of any disease, I was hoping you could advise me on this.



Ahh, I am a big fan of the Vectron line of Ultraviolet Sterilisers by Tropic Marine Centre... And though some folks do endorse using these... indeed all sorts of gear, like protein skimmers, ozonisers... on a punctuated basis, it is really best to leave them on continuously... For all the "things" that UVs can do... Decreasing overall water-borne microscopic life populations, increasing dissolved oxygen, increasing RedOx potential... About the only times I would shut off your UV is when you are servicing it, or using chemical treatments (e.g. Copper compounds) that the ionizing radiation will mal-affect.  Cheers, BobF

UV Sterilizer - Plumbing inline with a canister filter. 4/23/2010
<Hi Gary.>
Thanks for always answering my questions you are all very helpful, here goes again.
<Fire away.>
I was thinking of installing a UV sterilizer, but because I have only got Live Rock and a hang on Deltec Skimmer with no refugium or sump, I didn't want to have a pump in my tank to run it.
I know you can buy an external pump but a decent one is not cheap. So I have got a Hydor external canister filter that I don't use at the moment, I was wondering if I fit the uv sterilizer in line with the canister filter but also utilize the filter for chemical filtration carbon, Rowaphos and also put in about 50% live rock rubble, would there be benefits from this or can you suggest a better way to install the UV sterilizer although I am quite tempted to use the canister filter for chemical filtration and I like the idea of putting Live Rock in it.
<That is certainly feasible. The only concern I would have is ensuring the flow rate through the UV unit is correct - as they usually require a slower flow.>
<You can read more about them here: http://www.wetwebmedia.com/UVFAQs.htm
Thanks in advance
<My pleasure.>

Removal of a UV filter 02/07/2008 First off as usual let me give you guys praise for being such a wealth of knowledge. <<Hello, Andrew here, and thank you for the kind comments>> Since I have now been reading under UV Filters for about 30 minutes, and cannot find exactly what I am looking for I decided to write in as I have many times. Here is a description of my system: 125g Tank with CPR 1200gph overflow 4x96W Power compacts 2 Actinic and 2 10K Koralias #2 & #3 2 Powerhead 802s Rio 1400 running along back wall through about 90lbs of live rock Tonga Fusion, Fiji, one other kind that starts with a P. Red Sea Berlin Skimmer in the sump with a Rio 3100 on it gets me about a full cup every 5-7 days 55 Gallon Acrylic Sump with large refugium Section that has tons of life, 4-5" bed of sand Chaeto Algae, some Red unidentified Macro, Orange Tree Sponge, and lots of pods and baby stars etc. Lighted 24x7 and may switch to reverse cycle Little Giant 1100 GPH return pump that "t"s into 2 dual loc line returns over the back. Hang on whisper Filter running as a hang on refugium with 4" sand bed, Chaeto and a piece of the orange sponge. Also I have a Fluval 404? it is old school and all black, at least ten years old. I took out all the media and have just some live rock rubble in the baskets of all three layers. The fluval runs through a 25IL Aquanetics UV sterilizer and a Fluval surface skimmer. Both the Fluval and the Hang on Fuge were left over from before I had my sump going as I was inexpensively trying to improve conditions as I saved up for/built myself the sump. They have been running in tandem with the sump since just after the holidays, so I am ready to start removing them slowly. <<A nice setup by all accounts>> Inhabitants/citizens: 1 4-5" Yellow Tang 3 Damsels Yellowtail, 3 line, and the Black with white spots, I believe 2 or 3 spot domino they call them who I am ready to remove if he gets out of line :-) 1 Juvenile Chevron Tang 3-5" 1 Dwarf Flame Angel ( A site and personal favorite from what I have read ) 1 4-5" Foxface Rabbit who was only purchased to spread aggression when I added the Chevron, The Foxface may get traded back in the future 1 5-6" Blue Face Angel who was purchased on sale with slight Hole in the head before I was educated and found your website, but since I offer him a varied diet he has come completely around, beautiful colors, and the hole has gotten smaller over time. I know one day he will be too big, but I will most likely cry when I have to sell him or trade him. <<Its always amazing how attached we get to the inhabitants of the tank>> Anyways, it has been awhile since I wrote in and I wanted to make sure we knew what my system was before I fire away with a question. Here it goes: As this is a FOWLR tank, I test for the main factors in the Marine test kit. Nitrites, ammonia, Ph, Salinity of course, and Nitrates. I am sure you can see where this is going..... My nitrates have always been high. <<Specific levels??>> Everything reads 0 with ph above 8 and sg between 1.023 and 1.024 regularly Except for my nitrates. The tank has been going for about a year now, and was switched form crushed coral and UG filter plates to live sand and more live rock about halfway through its lifespan. Prior to that change the nitrates were absolutely blood red I mean off the charts on my test kit, but I never lost any fish. I did however have a very messy stars and stripes puffer, but I traded him for the Foxface and Chevron because I knew he was adding to the problem. Since I added the hang on fuge, and then the sump, the nitrates have come down with my regular water changes (20-30% monthly). But they still ride anywhere from 20-40ppm and I am aiming for zero or in my case at this point less than 10 would be GREAT!!!! lol <<I agree..10ppm is a more realistic area to aim for>> So here is the real question, and I am sorry for going on and on, but I am trying to answer everything you might ask as I go so we can avoid the old back and forth. :-) <<Its fine>> What will, or I guess could happen if I remove the Fluval completely, and in turn remove the UV filter?? <<If this is your plan, I would suggest adding another 30 - 40lbs of live rock, in small amounts, to build up the level in the main display of filtration. To answer your question specifically, by removing the HOB refugium, you will be removing part of the filtration in the tank. If the just mentioned additional amount of live is added, it wont make any difference. The UV, well, I don't feel you'll notice any difference>> I have heard varying accounts that UV filters are not needed, and or they should only be run at night for 6 hours or so, only confusing me further. I have narrowed down my source of nitrates to the debris that must be in the bottom of the Fluval, and therefore now I need to remove it, but that leads me to the UV filter controversy as it seems. My initial thoughts are to add say a Mag Drive or similar external 350gph or so pump in a separate closed loop out of my display through the UV filter, which will allow me to still use my Fluval surface skimmer, which in my opinion, everyone should have in their tank as it eliminates all surface debris completely. <<You only require a slow flow through a UV. If the water flow is fast, it reduces the contact time between water and UV, thus making it less effective. There are a lot of arguments regarding whether a UV is id good to have on a tank. Its ultimately down to the individual keeper to read through the pro's/con's of these devices and make their own decision based on these. Personally, I don't run one, not intend to run a UV>> Thanks in advance for even reading this long query, but as you can see I am fully addicted errrr I mean committed to the hobby and am trying to provide my little guys with the best environment possible. Douglas M. Payne Jr. (DJ) <<Thanks for the questions, hope this helps. A Nixon>>

Re: Removal of a UV filter 02/08/2008 Andrew, Thanks for your reply. <<hello again Doug>> Aquanetics recommends 520-750gph through the 25il UV unit. From what I have read this seems extremely high. <<Seems high to me too>> I originally was going to go with a Mag 35 but went with the 5 instead to account for the head. I disconnected and removed the Fluval yesterday and discovered a thick black sludge in the bottom I am guessing that is some nitrate rich stuff? <<The build up, of what sounds like detritus to me, is certainly not going to be helping the system>> I am going to leave the hang on fuge for now and am going to pick up 20+ lbs of live rock today as I have wanted more anyways for a while. <<Sounds great>> I hooked the UV up to the mag 5 drawing from the return section of my sump and flowing back into the skimmer/live rock section. So you really don't see any benefit of the UV personally? I have read up on it and it seems to be about 50-50 with some people and stores swearing by it. Just wondering your personal thoughts. <<A UV will remove not only bad bacteria, but also a level of beneficial bacteria too. So, its killing off microfauna as well as pest parasites. No discrimination here. They are handy to have in case of an emergency, like an algae bloom>> I will let you know if my nitrates come down as I am doing another 10-20% water change most likely this weekend. <<Thanks for the reply, and look forward to an update on the nitrates>> <<Hope this helps. A Nixon>> Thanks again! Douglas M. Payne Jr. (D.J.)

How to clean a UV bulb 10/2/07 I have a UV bulb that has calcification on it after 2 months of use. How is one supposed to properly clean a UV bulb? Thanks, Hank <In this sort of case, I'd first try simple (likely "white") vinegar and a sponge... wiping... maybe with gloves on your hands... if you're sensitive to dilute/weak acids. Wiping such lamps down regularly (every few months) with a cloth, perhaps alcohol (rinse in water after of course) generally prevents such scaling. Bob Fenner>

UV Steriliser 06/14/07 Hi guys, <Mike> I installed a new uv sterilizer about 3 hours ago and now the water has gone cloudy. Is this normal? <Does happen... a bunch of chemical, biochemical, biological changes going on... should clear in a few hours time hence... In the meanwhile, if livestock are present, do keep your eye on them... be ready to either move or change a good deal of the water out, turn the UV off until the water clears... put on a few hours a day till the system re-centers with less free-floating biota, higher ReDox... BobF> Cheers Mike

Downside of not running UV Sterilizer 24/7?    5/12/07 The water in our office 75 gallon marine tank turned milky over the weekend several months ago and I discovered that a snail had died.  Despite a  number of 25 % water changes, the water never cleared up, and in fact turned  very green due to the use of tap water. <Mmm, something more at play here... Inadequate filtration and/or circulation...> This week I decided to buy a UV  sterilizer and hooked it up last night.  This morning the water was  basically crystal clear.  My question is, for water clarity purposes, what  would be wrong with putting the UVS and pump on a timer and have it come on for  24 hours just a couple days a week, if that is all it takes to keep the water  clear? Thanks,   Condre' <Not "wrong" per se, but it's better to run such devices continuously for all the good they do. Please read here: http://www.wetwebmedia.com/AqBizSubWebIndex/bizuvs.htm and the linked files above. Bob Fenner>

Optimal Flow Rate for Jebo 11W UV Sterilizer  11/21/06 Hi there <Howdy> I've just bought a Jebo 11W UV Sterilizer - however, it does not come with much instructions. I would like to know what would be the optimal flow rate of water through this UV sterilizer? My tank is 200 liters. Cheers Tim <Mmm, strictly speaking there is no upper limit for such units in closed system applications... That is, the "kill rate/ratio" will be less per pass if a certain optimum flow rate per hour is exceeded, however, more water passing by within the critical minimum distance of the UV lamp will render just that much more in-suspension life more deleterious dosage... Likely a practical flow rate is somewhere around 40 to 60 gallons per hour... Bob Fenner>

UV sterilizer 11/6/06 Hello! <Hi> I just started a new 75G saltwater aquarium from scratch. Is that o.k. if I run my UV sterilizer while the water is cycling? Thank you very much for your time ! Sonny. <Should be fine, may slow down the process a little, but no big deal.> <Chris>

Wipe out Hi James,  <Hello Deb> As of today I lost all of my fish. <Sorry to hear this.>  I had the LFS service come to my home and he said he felt I had a bacterial infection going on based on the look of one of my fish I saved for him. The fish had a pinkish to light red line going down him. He installed a UV sterilizer for me and said to give the tank 5 days to rid of the bacteria then add one fish as the tank could be without fish this long. I have two cleaner shrimp and five small snails left, everything else is gone. I am so discouraged by this whole thing, as well as upset that we lost such beautiful fish.  Is this the correct procedure, is 5 days long enough to wait? All levels in the tank are where they should be so water quality is not a problem. He said he would not treat with medication as that disrupts the whole system, that he would let the UV do its job. Any thoughts and advice are appreciated.  <Deb, first of all, a UV is only going to kill what goes through it. There is no guarantee that all the bacteria will be killed. I would let the tank run for at least three weeks if not four. This way, if there are any parasites (ich) in the tank, these should die off also. Then I would consider the use of a quarantine tank for new arrivals before they are put into the display tank. James (Salty Dog)>

FW Stingray kiddie pool, UV sterilizer effect on it Hello, I have a 900 gallon swimming pool in my basement for freshwater stingrays.  This is the kind of pool you set up in the back yard for kids to swim in. They call it "Easy Set Pool".  All plastic pool.  Been running fine for 4 months now, no problems. I was told the pool itself is fish safe??? <Should be... if the plastics were toxic you would know so by now> I just added a UV sterilizer to it yesterday. Is the UV safe with the pool itself? <Should have no effect> Just want to make sure the UV won't interact with the pool material. Any info would be so much appreciated. I value your time and answer. Thank you for the awesome web site ! Regards, Darrel. <Ultraviolet sterilization will elevate the pH of the water a slight amount, increase redox potential, "burn" up some organic constituents in the water... makes little difference to the container itself. Bob Fenner>

UV Hi everyone, I was getting ready to purchase a U.V sterilizer for my 125 gal. The tank is only 4 weeks, and is now cycled. At what point can I add a U.V sterilizer ? I had read not to use them on newly set up tanks. Also I had a 9 watt Coralife Turbo twist for my 55 gal, it said it treated up to 125 gal. but I have read a few places that I would need a 25 watt for a 125 gal. Really confusing. I want to get the correct wattage, any advice? By the way, sorry for the capitalization problem, I am working on it. Thanks for answering so many silly questions. And don't worry, if I get any new fish it will be months from now, I just like to plan ahead and research so I don't end up with an incompatible or non-hardy fish.  <Kim, here is a link on UV worth reading for a better understanding of it. James (Salty Dog)> Thanks again for your help, Kim  <You're welcome> <Marina greatly appreciates your efforts with capitalization!  Makes my job much easier.> 

UV Question 8/2/05 Hello; <Hi there> I once sent a mail to WetWeb. I didn't receive a reply. In case you recall that email and my name attached to it, I thought to add a humble apology. At that time I was relatively new (still am though) to fish keeping, but at the same time I didn't want to come across as unknowledgeable for some reason. I was likely tired and frustrated that evening trying to find answers on-line to my problems. So I may have "over-stated / emphasized" some need to establish a lack of ignorance on my part while asking questions. I likely did not come across well - so sorry. <No worries> I have been reading on WetWeb for several months. I wind up in your archive somewhere every time I have questions. Thanks for having that info available free to the public, and thanks up front if you have time to assist me here, please. <Welcome> UV Sterilizers: I've read through your UV info; but could not find info regarding over-sizing UV's and effects on temp. <Usually not a real issue... as the wattage described is not the watts added... especially with most modern units that are sleeved...> A tech aid at Dr. Foster&Smith recently told me that you cannot go too big regarding UV wattage. <Practically this is so> Also - they post a chart stating required flow rates for parasite kills. (btw - I have read your statements regarding UV's actual effect on parasites and the narrow range / requirements within which any benefit exists. I understand UV may not be an effective guard - and I do use HT / QT, btw.) <Ah, good... UV is a useful adjunct....> Even still I plan to purchase UV's, and to use this simple standard (running the Turbo Twist models): -- On QT / HT I'll run 9w UV in-line using a Hydor Prime-10 (80 gph) -- On all tanks less than 55 gal I'll run 18w in-line to a Hydor Prime-20 (155gph) -- For tanks 55 gal to 90, I'll use 36w and a Hydor Prime 30 (230gph) -- anything bigger I'll use 55w UV +,  and maybe a Filstar XP3 (350gph). My concern is if I use, say, an 18w UV with a Hydor Prime-20 on a 20gal / 30gal tank - or a 36w on a 55gal tank - (using the Hydors), then what would be the temperature effect of this over-sizing / low flow-rate attempt? <Almost negligible, as you will find> Will I need a chiller? <Not unless you need one already> I have an air-conditioned home; but in the summer my tanks always stay about 80 deg F regardless - so I'm concerned that  the larger UV's will only lead into chiller costs too. Thank You Scott K <These fluorescent UV lamps run quite cool. No problem. Bob Fenner>

UV sterilizer flow rates 01-06-06 Hello, <John> Happy New Year!!! <Same to you and yours.> I just purchased a 36 watt Coralife UV sterilizer for my 125 gallon reef tank. My question is on the proper flow rate needed to zap Crypto (protozoans)? The manufacturer suggests a flow rate of 290gph. I did some research and found that a slower flow rate about 100gph is better for zapping protozoans. What do you think? <The slower the flow, the greater the U.V. exposure to the water in the chamber. The only drawback to this is the amount of heat generated by the bulb. The problems you may see with a lower flow rate is increase in heat transfer to your tank and possible damage or early wear on your equipment. With only a slight increase in efficiency I personally could not justify risking my equipment, but that is a decision you will need to make on your own. As a side note, U.V. sterilizers are not normally used on reef tanks due to their inability to tell friendly organisms from their intended targets.> I plumbed it in my sump with a dedicated power head. I can adjust to inflow with a small ball valve if need be...Thank you to the entire WetWeb crew hope all your holidays were joyous....See ya John <Happy Reefing, Travis> UV/Vitamin C/Lionfish Behavior - 03/02/06 Dear Eric <<Hello Akila>> Thanks for the advice. <<Always welcome>> I got hold of a 9W UV sterilizer and installed it to my main tank. Do you think this is good enough for the tank? <<It can be beneficial to your FOWLR system, yes.  Do be sure to keep up on the maintenance of this device.>> I fix it to my canister filter's output & hope this will do some good for my tank.  Do you think this UV will increase the tank temperature to damaging levels? <<no>> I read so many articles that said Vitamin C supplement is very good for Marine Fish.  It's pretty hard to get hold of such at the LFS.  So is it possible to use a Vitamin C supplement manufactured for Humans and soak or inject with food and feed fish? <<Hmmm...ascorbic acid is just that, but I think the vitamin C supplements manufactured for aquariums are "buffered" differently from those consumed by humans (Bob, please feel free to interject here).  Under your circumstances I think it is worth trying, but keep an eye on your system's alkalinity.>> Also my Lionfish seems to be doing well.  He eats very well and seems to be free from any infection up to now (fingers crossed!!!). <<Excellent my friend.>> He doesn't swim a lot but, he stays in one place most of the day but swims a bit in the late evenings and early mornings but when he sees food he seems to be just fine and very alert.  Is this normal with Lionfish? <<Typical behavior, yes.  These fish tend to "hide" during the brightest part of the day.>> What do you think?  Is this something to worry about? <<Not at all.>> Appreciate your response Thanks Best regards Akila <<Very welcome, EricR>> UV/Protein Skimmer Once Again I am calling on your wonderful help. <Welcome back!> We purchased a UV Sterilizer for our 75 gallon soon to be reef.  Would it be ok to have the water that comes out of our protein skimmer be the water that enters the UV Sterilizer?  Both machines have the same pump. Thanks Annette <Do you mean a direct connection?  As long as both the skimmer and UV unit receive the correct flow rate and there isn't a bubble/air trap (from bubbles in the skimmer effluent) there is no problem. You might tee both off of the same pump, separately.  Craig>

Cleaning of U.V quartz sleeve I am using a 4 x 30 watt Aquanetics quartz sleeved pond U.V on a centralized store system.  I would like to know how often you would recommend cleaning out the unit and how I might best go about the process.  (I recently enjoyed seeing Mr. Calfo speak in Orlando...he was great!) <About once a month in the season when water is more than 65 F. is about right. Turn unit off (unplug), remove compression fittings and VERY carefully remove and wipe sleeves down with a paper towel (in tough cases with an alcohol as a solvent)... taking care NOT to touch the sleeves to anything hard (they will break... easily). Bob Fenner> thanks, Dave

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

Ozone Output From UV Sterilizer 10/09/05 The most common opening line! You have a wonderful, wonderful site! And I mean it!  <<Thanks.>>  Anyways, I have purchased an AZoo 13W PL light UV Sterilizer for my 120G tank. I know these things are not 100% effective but can be helpful. Anyway, this sterilizer has an option wherein I can let air into it, something like the power head operated skimmers have. The box claims that after the air passes the PL lighting I will get O3 at the output. My questions are: How will O3 help in my FOWLR tank? Secondly should I connect the air intake or not?  <<Please read up on the ozone so you can determine whether you need/want to run ozone and if so, whether a UV sterilizer is the best way for you to do so.>>  If yes I don't have anything to regulate it other than the normal valve we use for air pumps? <<Ozone should not be added without some way to monitor it's affects and regulate. Ozone can harm your livestock and damage some components. Consult the manufacturer for their recommendations. In my opinion, if you determine that you want to run ozone, you are better off running an ozone generator and regulating the ozone with a controller. Again, there is lots of information on this topic on WWM.>> Thanks in advance. Keep Rocking <<You're welcome and good luck - Ted>>

Lighting and U.V I have (one year) a 100gallons marine aquarium, 22" Height, 5 fishes, 3 soft corals, 1 small Tridacna, 5 hermit crabs and 1 red starfish. Lighting: 3 36w Power-Glo and 2 36w actinic. Kalkwasser is added 3 or 4 times a week ( total:1 gallon) 10 gallons sump top-off DI water In the present some slime algae are giving me some trouble and work because I must brush them off and clean the mechanical filter often. Recently (10 days ago ), one U.V sterilizer is in place in an attempt to minimize the algae problem and at the same time, to face a 12 days ago ich problem. So, I would like if you could give me your important opinion about the following: - the lighting.  - If I add, in the sump, some Caulerpa, what kind of light must I use there? Full spectrum fluorescent lamps? - When must I disconnect the U.V unit? Today the water is very transparent, the fishes are great and the corals are looking very healthy.  >> Your lightings okay (but could be brighter...) but do check the age of your lamps... they're really only good for 8-10 months at 10-12 hours per day... and should be cycled out one a month...or so. Do add the Caulerpa... and another or larger sump if it will fit... and yes, the full-spectrum fluorescent lighting as well... Maybe you can get a Compact Fluorescent for the main tank and move a couple of the current fluorescents down below? You never have to disconnect the UV and I wouldn't ever... it's made for constant use...  Bob Fenner

Copper and UV's I have read all through WetWeb and do not see any information on this topic so here goes. I have been treating my tank for marine velvet with copper and after a number of weeks  <These treatments should go no longer than two weeks...> I believe I have saved at least part of the fish. The tank is now velvet free for two weeks. I am beginning to drop copper levels but it is proving pretty tough. The tank took almost 5 times the normal copper dose to finally get the required free level of copper in the water. <Absorbed where?> I am currently doing water changes and have a copper absorber in the Modu filter but copper levels have not budged at all according to the test kit. Copper will drop right after the water change but jumps right back after 24 hours or so. I assume it is still leaching out of the substrate etc. The copper I am using (Cuppermine)<Cupramine> said to turn off the UV during use. I did this but want to turn it back on as soon as possible. Why exactly did I need to turn it off in the first place and if I turn it back on what will happen?  <The method of chelation is defeated by UV radiation... may coat your sleeve or lamp at this point even...> Release of too much free copper, UV coated with copper, thermo nuclear explosion? This as been a long battle and I sure don't want to mess it up at this point. Help and thanks as always. <Place activated carbon and/or a pad of Polyfilter in your filter flow path and the copper will be gone. Bob Fenner>

UV Sterilizers Hi There! I have a question about UV sterilizers. Should they be run 24 hours a day?  <In most cases, yes> We use live rotifers to feed our 75 gallon reef tank and we've been told that the UV should be turned off after the main lights go off and our actinics come on, because the UV will kill the rotifers when they come out to feed on algae. Is this true?  <No... not in my experience... Rotifers are large enough to persist through exposure to this amount and kind of radiation... In comparison, probably much more of their numbers are reduced by various pumping mechanisms in your system...> Are enough rotifers living in our tank for the UV to have an impact on their population? <I doubt if this is an issue... and if I had a UV in your situation, I would leave it on continuously.> Thanks for any input, Kristin Gardiner <You're welcome. Bob Fenner>

UV use and Copper  Lorenzo, as it turns out it seems to be ich again, i did re-copper the tank using copper power, i think the queen was actually stressed from moving a sump sponge that was filled with waste, i do have Caulerpa in the tank (hopefully putting a small dent in the trates, still green as ever, the queen is still acting weird, and eating little if any. What i really would like to do is a mass water change, but there is so much water to replace. Can i run a UV sterilizer while having the tank coppered?? <Not with some types of sequestered copper. Check the label on the Copper Power re. Bob Fenner> thanks

NYLON and UV Hello Bob, I installed a UV sterilizer and was forced to used nylon adapters from 3/4" female to 5'8 " hose. The light is emanating from the nylon (white) adapters causing them to glow. Will the nylon break down due to the UV light?? <Over a period of time, yes. I find it a good idea to replace these fittings about once a year, or approximately every two lamp replacement cycles... maybe record such on the contact chamber... And a likely-unnecessary warning... don't stare (much) at the area where the "neat purple light" is shining through (and do place such out of the view of pets, children (or tape, wrap over)... Bob Fenner> Thanks, Russ

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

Ozone & U.V. I told you I had a two part question but couldn't think of a great way to formulate it. I've read your book and perused WetWebMedia looking for an answer to a specific question about ozone. I want to start using it in small amounts in my Top Fathom TF300 skimmers. If any residual ozone is passed through a U.V. sterilizer will it be destroyed or converted back to standard oxygen? <You can do experiment/s to ascertain this yourself... mainly it will pass through and be added to by the UV's action> We are talking about the small amount generated by the tiny "Coral life" brand ozonizers set to low. No output level was stated in the destructions but I have noticed a major performance boost in the skimmers the few times I've used it. My concern is ozone getting into the main tanks and rotting the rubber O rings on my bulkheads? Ozone is an after thought so I never checked to ensure these gaskets were U.V. resistant. <Ah, not a problem. Very little ozone involved, almost none that gets as far as the tank itself. Bob Fenner>

Best Use of a UV Robert, <Steven Pro this afternoon.> Hi again. I just purchased a 30 watt UV sterilizer for my 180 gallon fish only tank. Before I set up the UV unit I would like to know a few things first. For a 30 Watt 36" bulb, what is the recommended flow rate for killing Protozoan Ick and other parasites? <I would use your manufacturer's recommendation.> How many gallons per hour pump & what model should I get. <Get a pump rated for just under the manufacturer's maximum flow rate and please prefilter the pump.> Where do I place the pump, in the tank or in the main sump? <The sump would be better; water cleaner, less of an eye sore, etc.> Do I collect the water from the main tank or one of the sumps? Do I return the water directly to the tank from the UV or back to one of my sumps. <To the tank or the other sump as long as the water is moved about.> I need to know the most effective way. THANKS! <You are welcome. -Steven Pro>

Re UV: I have been told the best placement for the pump to the UV is about an inch or so above the substrate because that is where most of the pathogens reside. This 50g with the Amyloodinium is a Uniquarium. There is a separate filtration area behind a false back. Water from the front display area overflows into the back, thru the filtration and returns to the front of the tank on the other side. Would the UV be just as effective if the pump were to be placed in one of the back filtration areas? <In practical application, yes> Re nutrition in a Q tank: You said "Sorry for the ambiguity. I mean/t soaking in a vitamin preparation, iodide solution and possibly HUFAs (highly unsaturated fatty acids)" What vitamin preparations or HUFA preparations do you recommend? <Selcon, Micro-vit... ones you can make yourself> Re iodine: What is the purpose of iodine? <An essential nutrient for many forms of life, as a disinfectant, "immune system booster"> Under what circumstances and conditions do you feel it would be warranted? <Regular administration (weekly generally) to system water, to foods daily in some applications (treatment, aquaculture)> Which iodine preparation would you use? <Potassium iodide. Am not a big fan of Lugol's> How much? How often? <Mmm, much to state here... "measurable" next day by experimentation is my best response... w/o launching into a necessarily at-least-article-length monotribe of what is involved> Re: Nutrition in general: Would any or all of these supplements be a good addition on a regular basis? If so how often? <Mmm, yes... some daily, others more like weekly... vitamins in particular> I read about Vitamin C supplementation on the site. How much and how often would you recommend the addition of this? Does it have any effect on water quality? <Daily to weekly... as with humans, not much downside to "over-supply". No practical consequence to adding to aquarium water quality unless unrealistic amounts are added> Thank you again as always, Leslie <Thank you my friend and fellow aquarist, lover of life. Again, my apologies for the delay in response. Bob Fenner>

UV sterilizer I have been working with saltwater and freshwater fish for two years now. Currently I have a 46 gallon bow front aquarium with a emperor 400, Prizm skimmer, and a VisiTherm heater.  <do upgrade the skimmer as soon as possible (before buying next fish/coral)> I also have about 15 pounds of live rock and some invertebrates. all my fish died from ich) Through the years I have had success and failure and really want to get the failure to go away. I have had the most problems with my saltwater tanks and have learned many lessons in the process.  <hopefully quarantine all fish for 4 weeks without exception was one of them <wink>> I have two questions I have been trying to get answers to for weeks now. The first is do you think I need to add a medium sized canister filter to my tank.  <nope... a fishless invert system would benefit by far with more rock before it would a canister filter> The second question is a little more complicated. I have just purchased a 30 watt U.V sterilizer for my tank with a Rio 1600 powerhead to run it.  <a huge UV for this tank and the water pump is too fast/strong for effective kill time I suspect (consult mfg recommendation for flow rates)> I haven't hooked it up yet but is 30 watts too much for my sized tank. <not too much... but larger than necessary. No harm though> I got a good deal on it and I hope it will keep the parasites off my fish and reduce the algae problems I have been having.  <you will be disappointed about the fish part but delighted about the algae control. UV filters can only kill free-floating parasites... but if you do not QT a fish and bring one into the display with parasites on the body, then they stay there, drop off and some jump back up onto the fish without ever passing through the UV. UV filters have a very strict range of terms under which they will control pathogens... do review archives and FAQ's on this topic (especially recent FAQ's). Any tank with gravel or sand will be difficult to control parasites in if you make the mistake of not QT them> Do U.V sterilizers really help with these problems.  <bulb must be less than 6 months old, water flow slow, water crystal clear and prefiltered (carbon weekly ideal), etc> Thanks for your time and I hope to hear back from you soon. <best regards, Anthony>

UV Fixtures I have just started a saltwater fish-only aquarium. I have bought a Custom Sealife double helix UV (38 watt). They say that the longer the exposition to UV is the better. My problem is with the water flow rate. They recommend between 100 gph and 500 gph. What rate should I have for the UV to be the most effective. <The slower the flow rate, the greater the kill rate and number of things killed. Speed translates to contact time. It is comparatively easy to kill free-floating algae. The next hardest (requires more contact time) is free-floating bacteria and lastly is parasites.> Also how many hours a day should I leave it on. <24/7 for maximum effectiveness.> Thank you, Jean-Yves From Montreal <You are welcome. -Steven Pro>

UV Sterilizer <<Greetings, not Bob but JasonC...>> Hi Bob I really enjoy the website. Just a quick question though. I just purchased the 9 watt custom SeaLife UV Sterilizer. It looks like the water goes through a coil tubing around the bulb.
<<Ahh, this the Helix, the new UV unit from CSL, I presume.>> What should be done to maintain this product in the future to maintain its effectiveness (cleaning, bulb replacement, etc)?  <<Well, replace the bulb as the manufacturer suggests, that is a good place to start. Then cleaning, may not actually be needed because the aquarium water doesn't actually contact the bulb. Again, I would stick with the manufacturer's directions.>> Thanks for the help! <<Cheers, J -- >> 

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