Was: Sea Star Regeneration? – now nitrates and DSB 03/12/08
Hi Marco,
<Hello Ross.>
Thanks for your quick and informative reply.
<No problem.>
The sand has been a slow process.
<Good.>
When I started the was only a half inch to an inch of sand. Uniformly there is now at least 3 inches but there are places that have 4 or more.
<Okay, 4 inches is considered by many as the minimum for a working DSB, but that also depends on the current and grain size, DSBs can work with 3 inches. I’d try about five inches for your 100 gallon tank.>
I'm still working on adding more. I do have bioballs, but I bet they should be cleaned.
What do you think?
<Personally I’d try to remove them with time to see if there is any impact on the nitrates (they are sometimes referred to as nitrate factories). Especially if the water runs through them before it reaches the skimmer, bacteria on these balls do break down proteins before the skimmer can remove them.>
I do a 30 gal change once month and try to do a 5 gal change once every week to two weeks.
<Should be more than sufficient for your 100 gallon tank. I suppose this water is free of nitrates?>
On a good day the nitrates are 40ppm on a bad day its 160 ppm which seems outrageously high.
<Indeed and possibly a cause of the death of the sea star. I think adding more rinsed sand and slowly removing the bioballs will improve the situation. Overfeeding could be another reason for high nitrates, you probably know better than me, if you are feeding too much. If slowly removing the bioballs and creating a DSB should not help, my next step would be a better skimmer.>
Thanks again. Ross.
<Anytime. Cheers, Marco.>

DSB or BB, Deep Sand Bed Utilization 3/5/08
Hi Guys!
<Hello>
What would happen to the hobby if you were not there!
<Probably see a few more sharks shoehorned into a 20 gallon tank.>
As again I come back to you. I have 36"W x 30"B x 30"H reef supported by a 36 x 12 x 12 sump with a filtration using sponge (NO BIO BALLS). I have approx 80Kg of LR. I always faced a problem of high No3. Hence 6 month ago I decided to go bare bottom on the same tank. Today I again face the same No3 problem. So a friend of mine suggested I go for a DSB like his (wherein he got 100Kg of sand from a beach for his DSB) and add another 20 Kg of LR which he has spare with him. I was thinking of doing the same. But this time I want to make sure that my no3 issue is resolved once and for all.
<The nitrate issue is often caused by overfeeding and too infrequent water changes, while a DSB can help, its not a magical bullet.>
It also crossed my mind that the LR i am using could be faulty too. So my questions are: 1) Should I go for DSB or a BB is better?
<Its a matter of execution really, but I use a DSB.>
2) Should i go for a complete new set of LR?
<If it is more than a couple years old I would think about switching out maybe 10%, but no need to replace it all.>
3) If a DSB is the sand from the beach (clean) suitable?
<I would not, the risk of chemical or biological contamination is too high.>
Thanks in advance
Regards
<Chris>

Coil Denitrator Question, refugiums, using WWM     2/16/08
Hi Crew.
Been awhile since I have been here which means all fish in all six tanks are doing well. I do have a question on a new thing Im trying that I can't find out much about is a coil denitrator.
<Ahh! I tried to make these commercially... twenty some years back...>
I made one and it is what it is just a big tube with coils running down the inside with a bunch of media in the center.
<An apt description... Ours were contained further (to keep all in the dark, discount photosynthates (e.g. algae) in a "clam shell" (a close-able container), and fed a stock solution of carbon... various alcohols and sugars were tried... Nowadays I'd like to run experiments with some dilute organic acids (e.g. Acetic...)>
I have seen little on what to expect from the water coming out and cycling time.
<Mmm, have to experiment... and what one will get is going to be a function further of what the incoming water make-up water is... but the pH should drop, there should be less measurable NO3...>
I let run one full day wide open and then shut it off for a full week with water sitting in it. I turned it on and checked the water coming out and I had zero nitrates and zero nitrites but the ammonia was high. Is that normal or will it cycle to the point where I don't get any ammonia reading?
<Should... the water needs to run through slowly... as in a drip...>
I was very excited when I did my 1st test and seen zero nitrates though but I don't want to swap them out with ammonia though. I have been struggling with nitrates in my 125 gallon since I set it up over a year ago and know about the bi weekly water changes cleaning of the filter sponges and filter floss on a weekly basis but never do I get my nitrates under 80ppm.
<Yikes... you've read on WWM re?>
Well once but that was months ago. All fish are doing well so I don't fear them getting sick but would love some help in getting nitrates down.
<... Read: http://wetwebmedia.com/nitratesmar.htm
and the linked files above>
Im going to have to take all six tanks down in a few weeks and move them to my detached garage account of my house has to be tented for termites. Not looking forward to that but when I do Im going o try a remote DSB in the 125 gallon. I have read so much good about them Im hoping that will help.
<Should... you'll likely be a convert, soon>
The tank is a 125 gallon and is 6 feet long. Im not sure what size tank to use for the remote DSB?
<... is posted: http://wetwebmedia.com/marsetupindex2.htm>
Will a 20 gallon high make a difference are do you think that is a waste of time and to small?
<Bigger would be better...>
Is there a certain way to gauge that? I also have a 220 gallon someone gave me and want to set up but if I cant find a way to combat these nitrates I don't want to set it up with the cost of the weekly water changes it will kill me. Well crew as always thanks for any and all help. Your site has saved many a hobbyist from going back to drinking for a hobby Im sure.
<Funny... it's had quite the opposite effect on me. Heeeeeee! Bob Fenner>

SW questions, Cnid. comp. and NO3 reduction  – 1/26/08
Hi Crew,
My first question is about lighting. I have a 10 gallon which is almost 5 years old. It has 4 different candy canes with a total of about 40 heads.
Also four hairy mushrooms (browns with blue lines) that are from one original.
<Would be very big trouble if introduced all at once...>
All my other mushrooms (reds, greens and blues) have shrunk and just disappeared.
<To be expected>
In fact there always seems to be one that does great and the others either just hang in or start shrinking.
<Bingo>
I have 65w PC's. The bulb I currently have is 10k and it will need to be replaced soon. Should I continue with this or can I go with a 50/50.
<I would not change>
I plan on staying with
candy canes and mushrooms.
<And not add any more/other Cnidarians>
I have lots of coralline on the glass and very little on the rock although it has started to increase on the rock lately.
My second question relates to nitrates. I am under the impression that it takes a DSB to have bacteria to process nitrates and if I do not have a DSB then water changes and/or a skimmer will help reduce it, water by dilution and a skimmer by eliminating the source pollutants.
<Actually, not so... for biological conversion (denitrification) requires some/any sort of hypo- to an-aerobic setting/media, very low flow rate through, thereabouts... Doesn't have to be... a DSB>
The first 3 years that I had my tank my nitrates were usually around .20. But for the last 2 years it is zero and I do not have a skimmer and I change 1 gallon every week. Does that mean I do have some nitrate eating bacteria or is my test kit on the blink. I use one of the cheap test kits (AP's master kit).
Thanks
<Likely there is no appreciable NO3... Bob Fenner>
 

Nitrate reductor water chemistry – 1/2/08 Hi Everyone, <James> A Happy New Year to You All, <Oh yes> I have a Bubble King skimmer and an Aquamedic 5000 baby skimmer working on my system of 3500 litres. . I added an Aquamedic nitrate reductor 5000 a few months ago. The water coming out of the Nitrate reductor is messing with the skimmers bubbles and stopping them producing any foam. <Mmm... perhaps a different arrangement of where these devices dump, mix their discharges> The bubbles at the top become very turbulent.. I now know for sure it is the no3 reductor as when I remove it from the system, the skimmers start to skim within hours. Put the reductor back on the system and the skimmers stop all together. I have done this 3 times with the same results. If I put the reductor outlet pipe straight into the main tank it takes a little longer to affect the skimmers. If I put the reductor outlet into the sump (where the skimmer supply pumps are) then it effects them within minutes. <What sort of water quality test devices do you own? Would you please check the discharge effluent from the denitrator? It may need to be turned down> Could it be the reductors oxygen less water and low mv? <Yes> Is there anything I could do to the reductor water before it enters the main system? <Aerate it mostly... or add an ozonizer (which I definitely WOULD have in a system of this size/type) picking up, discharging the denitrator-mixed water in a sump...> The reductor really works. The water coming out is zero nitrates. I am controlling it with an mv control. My nitrates are high but I doubt they will come down much with the skimmers not skimming. I do also have a large deep sand bed. Many Thanks, James. <Mmm... do you have this DSB outside the main system? What sorts/amounts of foods? Have you a purposeful refugium, macroalgae culture here as well? I would look to other means to augment your overall filtration... Bob Fenner> Re: nitrate reductor water chemistry 1/2/08 Dear James, Thank you for your reply/advice. <Welcome> The water coming out of the reductor has zero nitrites and zero nitrates. Anything else I should test it for? <pH> When the mv gets to -250 it turns on a supply pump and pumps water through it for a few min.s until mvs are -200 or so. This process continues 24hrs. <I see...> That's a great idea. Will this work? - I set up a very small tank with tank outlet pipe into the sump. It can be at the end of the sump near return pumps and away from skimmers. I hook up my ozonizer along with another small skimmer and another mv control. I can also aerate the water in the small tank with powerheads. If you like this idea I will get going on it straight away. <I do think this is spiffy> In answer to Bob - Yes, my DSB is in a 50 gallon tank and is 17cm deep. It is connected to the main system. I don't think it is enough for the 3000/3500 litre system. <Not even> Sugar fine aragonite costs as much as gold over here so adding more DSBs is too costly. <Mmm, time for some importing on your own perhaps... next vacation, business travel> I struggle to find macro algae here in south Africa. I may be able to get Caulerpa though, is that ok? <Likely so> I feed Ocean nutrition flakes, pellets, frozen foods, prawns, calamari, seaweed. Everything really. I have 15 big fish (tangs. trigger, angel) and 15 little ones (damsels etc.) I think with the skimmers not working properly the nitrates keep going up anyway. catch 22. Thanks again, James. <Welcome! Bob Fenner>

Nitrates, SW, RDSBs  12/07/2007
<Hello Craig!>
HI I have a 265g tank that is mixed reef - but mostly LPS. I have an additional 70g circulating thru a sump/fuge and wet/dry that was modified to be a skimmer compartment. No bioballs just rock rubble. I did leave one drawer for a filter pad which I change weekly religiously. I'm running a 3600 pump and splitting it as return/spray bar. I also have 4 Koralia 4's.<A wave timer would work great with these.>
I have a nitrate problem reading about 25ppm (Salifert) phosphates 0 (Salifert). Last weekend I did a 100g water change - no results.<Not surprising.>
Second I have some diatom as a result of some RO/di problems that have been fixed. With w/c I still have some diatom but it is decreased.
<Clean RO/DI water will help. Make sure you test your Ro/DI water with a TDS meter (Digital) and that it reads 0ppm>
Third I have algae almost like hair but very short strands all over my glass and I have to clean it about every 2-3 days or it is EVERYWHERE.
I don't have a DSB in my main tank but do have about 20lbs live sand in my fuge = to about 5" I also have Chaeto/mangrove.<Some phoSarHC from Warner Marine would help greatly.>
I feed every other day homemade food along with Nori everyday ( I have 5 tangs).
I can't seem to get the nitrates down - I thought 100g's would have done it but it didn't I need help!!!
I have about 15 fish the largest one is a Naso about 6" all others are much smaller Please help.
<This sounds like you could use a Remote Deep Sand Bed (RDSB). You can plumb in a separate tank or a Rubbermaid Trash can(13gallon) with about 24" to 36" of sand and after about a month you will no longer have nitrates detectable. The bacteria in the RDSB will consume the nitrates as they are Obligatory Heterotrophic Bacteria and use the nitrate during respiration. Here is a link to the RDSB...
http://www.wetwebmedia.com/deepsandbeds.htm
http://www.wetwebmedia.com/livesand.htm
http://www.uberfrags.net/forums/showthread.php?t=1443
These links should help. After setting up a RDSB you should flow thru it about 400-600gph. The flow should be over the surface and not thru the sand bed like an undergravel filter would be. Until then, keep up the water changes.-Rich...aka...Mr. Firemouth>
Diver

Nitrate Levels And DSB – 11/29/07
Hello fishy-gurus!!
<<Hee-hee! Eric here... Not so much a “guru” as just a long-time hobbyist willing to assist/share my observations and opinions>>
I got a few questions regarding DSBs and nitrate levels.
<<Okey-dokey>>
I have a 430 Litre reef system,
<<Mmm, okay...about 113-gallons for those readers on “this side” of the pond>>
5cm of sand-bed (consisting of crushed marble and aragonite CaribSea sand sugar fine grade) and nitrate levels of over 40 - 80 permanently.
<<Yikes! Much too high, as I am sure you are aware. Just off-hand I’m thinking either reducing the depth of your substrate by half, or preferably, increasing the depth about three-fold should effect a change/reduction in Nitrates >>
I'm using the Berlin system with about 25kg of live rock. Other than that there are two Aqua One powerheads pumping 2500 and 2200 litre/hour and one Rio powerhead of 2000 l/h which is attached to my Aquasonic Venturi Skimmer. Because I have a chiller I had to connect an Aqua One Canister Filter (500L/H) to it, which contains Sponge and noodles.
<<Ah! A clue maybe! If you are not cleaning this canister filter media “at least” once a week then this is likely the source of your Nitrate issues due to the decomposition of the accumulated detritus>>
My inhabitants are:
1 yellow tang
2 maroon clowns
1 damsel
2 lawnmower blennies
1 white ribbon eel
<<Pseudechidna brummeri? Hmm, have you had this creature long? Though maybe not quite as “touchy” as the Rhinomuraena species...is still thought to be a difficult animal to keep>>
And 2 redline cleaner shrimps, heaps of corals and hermit crabs and one huge anemone.
<<Mmm, not a good mix...I hope the Actinarian doesn’t decide to go on walkabout...>>
I do water changes every two weeks of about 100 - 140 litres. I just read all I could on DSB on your website but do have the following questions:
1. If I want to add another 10 cm of substrate would it be ok to go half and half with CaribSea Aragonite and the other half of natural Ocean Sand (I live in Australia/Queensland on the coast).
<<It’s not usually suggested to use “beach” sand due to the possibility/probability for introducing harmful elements/pollutants. But, if you are certain the sand can be collected from a clean source there’s no reason you can’t do as you outline. You might want to also consider treating/curing the sand just as you would newly collected live rock>>
Other than the fact that the sea sand won't do much for my pH levels and the potential danger of introducing pathogens, will it do the same job for NNR?
<<It will... Just as buying some sand from your neighborhood hardware or home store would>>
2. I read somewhere on you site that you mentioned that the canister filter would have to be cleaned regularly because of the filter media in it.
<<Yes>>
Does the media inhibit NNR?
<<It doesn’t “inhibit” the process...but not cleaning the filter can allow nitrogenous compounds to accumulate faster than the DSB can process them, thus “overwhelming” the process of NNR>>
If this is so, I could just run the canister filter without any media in it!?
<<Indeed...but why waste an opportunity? I suggest you use this filter to hold a “chemical” media such as carbon or Poly-Filter...to be exchanged on a bi-weekly basis>>
3. What is the ideal amount of rock to have in my tank to help NNR?
<<Hmm...whatever amount is necessary to render a Nitrate reading of “zero” for the size and stocking density of your system and the quality of the rock used, along with your particular husbandry skills and maintenance habits... I don’t mean to be flippant, but only you can really determine what amount is going to work through testing and experimentation. My preference is to minimize the amount of rock in a system to allow room for growth of the corals and freedom of movement for the fishes, and utilize a large DSB for Nitrate reduction>>
4. How much would you siphon through the DSB to keep it working perfectly?
<<Sorry...you will need to clarify this>>
5. How is it that I am battling with such high nitrate levels and yet all my corals are doing well/growing and the cleaner shrimps are perfectly well, too.
<<Well...are you certain of the efficacy of your test kit? I suggest you try testing with new/different brand kits to validate your readings. Perhaps your Nitrate “problem” is not as it seems>>
I've got the beginning of the year. The anemone was a white colour with pink tips when I purchased her,
<<Bleached>>
she is now completely purple.
<<Excellent>>
Is she busy dying?
<<It would not seem so>>
I thought I works the other way around, they start of purple and turn white before they die?
<<Indeed>>
All my live rock is also covered in purple coralline algae??
<<Sounds good>>
Ammonia and Nitrite levels are Zero, pH forever 7.8 - 8.0.
<<I would adjust this up a bit>>
I'm struggling to raise it above 8.0 even when adding liquid aragonite regularly!!
<<Hmm...do let me know your calcium and alkalinity readings and we can pursue this further...and do say what this “liquid aragonite” product is as I suspect it is not of much help re>>
6. Do hermit crabs and other crabs add to your bio-load as fish do or are they beneficial (clean up crew) and therefore the more the better?
<<They do add to the bio-load, as does any living organism. They can be beneficial and, depending on your point of view, they can be a bane. I do not keep hermit crabs due to their “very opportunistic” eating habits, and I consider the commonly used Astrea snail to be more trouble than its worth...but...the vast majority of hobbyists do employ these critters as a “clean up crew”>>
Lastly-
7. One of the guys at the LFS advertised the Eco-System with Miracle Mud as so good that he hasn't done any water changes for 6 months and all his levels are ideal.
<<No such thing as a magic-bullet... Regardless of the methodologies used, I’m a firm believer in regular partial water changes>>
Have you heard of that and does the Eco-System reduce nitrate levels.
<<I’ve not used the Eco-System methodology myself but have heard much good about it. And the owner/perpetuator of this system is a good and much respected friend of Bob’s>>
If I install one, can I have it running in conjunction with my Berlin system and 15 cm DSB?
<<Certainly... I think it is a very good idea to have this or any other type of refugium methodology employed with any marine system>>
Also would it work to add Miracle Mud to my canister filter without light and algae growth?
<<No... The mud would prove to fine/would likely only cloud your system>>
And sorry this takes so long, if I don't want to drill holes and go the whole way, would it help to purchase a hang on Eco-System (not big enough for my system) and run it with the Berlin system?
<<Would still be of some benefit, yes...but much better to employ a larger vessel under the display tank...in my opinion>>
I appreciate all your suggestions and really would like to sort my tank out. thanks so much in advance.
Best regards, Jana
<<I’m happy to help, Jana. Eric Russell>>

Re: Nitrate Levels And DSB – 11/30/07
Wow, thank you so much!!
<<Quite welcome>>
That was so quick, too.
<<Does sometimes work out that way. Though even at its longest, most replies are made within 24-hours of receipt…that is, if Bob has his way about it [grin]>><Oh yes, sweep, sweep. RMF>
You guys must be taking a lot of time off to help others sort out their tank problems.
<<Mmm, nope…no “time off” as such for answering queries. We just fit it in when/where/however we can>>
To clarify some points:
The liquid aragonite is the 'AragaMILK' by CaribSea, and sometimes I actually have the feeling it drops my pH!
<<Hmm, indeed… I suggest you stop wasting your money…try simple Sodium Bicarbonate to boost your pH if needed. And do read here (http://www.wetwebmedia.com/marphalk.htm) and among the links in blue>>
I measured my KH which is at 125.3 ppm
<<Well, that converts to about 7.0 dKH…a bit low (should be between 8 and 12 dKH) and can't really say what my Calcium readings are - never had a test kit for that... :( I will maybe read up on its importance a bit.
<<Yes please, all are tied together (start here and continue through the associated links: http://www.wetwebmedia.com/martstkitfaq2.htm)…and very likely your low pH is due to an imbalance of Earth elements/bio-minerals in your system. If you stop all dosing, and do a couple or three 30% water changes a few days apart you should regain much of that “balance”…as well as diluting the high Nitrates…temporarily>>
You answered my question regarding beach sand with-
<<It will... Just as buying some sand from your neighborhood hardware or home store would>>.
Can one by "any" sand from the hardware store or would it have to be a specific one?
<<An “Aragonite” sand would be best, if available, for its buffering qualities. But any type of fine “play” or “pool-filter” sand will also serve>>
Are there no chances of chemicals being in there?
<<Will be fine>>
My question: 4. “How much would you siphon through the DSB to keep it working perfectly?” - What I meant was would you at water changes when you pump the water out, siphon through the sand bed to get the worst out with one of these "vacuum cleaners", or does this actually disturb the NNR process that's happening in there?
<<You will find those who would disagree, but I prefer not to “disturb” my DSB with such maintenance practices. Rather, I let the biota in the sand bed do any stirring/turning. You can add some Cerith and/or Nassarius snails to increase this activity if you wish>>
I think I have read different opinions on your site - so is there a golden middle between vacuuming and not disturbing?
<<Not other than utilizing the bio-turbators as I just stated…in “my” opinion>>
Before I emailed yesterday I had done a test on my nitrates with another test kit and the result also read over 40!
<<Not good…not good at all…>>
Anyway, I will get to my canister filter straight away, as I clean it may be twice a year only...Ooops.
<<Oh my… This is one habit you definitely need to change…once a week please! (No wonder your Nitrate reading is so high!)>>
By the way, my ribbon eel I have had for at least 18 months now. And before that I had seen him at the shop for at least 6 months.
<<Excellent… Perhaps this Pseudechidna species really is a bit more durable than the Rhinomuraena species of “Ribbon” eel>>
He is completely easy - although, I have to hand feed him squid.
<<With a feeding-stick I hope…>>
He is totally unable to catch any small fish by himself (sometimes I would bring tiny fish home from my visits to the rock pools…hopeless.)
<<Odd… And do rethink this practice of wild-caught live foods…much risk of introducing disease pathogens/parasites to your reef system>>
When I bought the Lysmata shrimps last year he got booted out to the quarantine tank for a few months because I worried he would snack on them. So I tried some shrimps from the rock pools with him and they survived and he was allowed back in the tank.
<<Again…odd that the eel shows no interest re these small live food items>>
The only fish I have not been able to keep is the emperor angel - I tried three and all died suddenly without any signs the day before...Naturally I'm a bit discouraged to give it another go as they are with the most expensive fish here.
<<Probably due to your water chemistry/pH and Nitrate issues. But really, your tank is too small for the long-term good health of this fish, anyway>>
Thanks again for your time and wonderful advice.
<<I hope it is of use>>
Best wishes, Jana
<<Regards, EricR>>

Hi Bob, it's Niki...again. NO3 in Wholesale Marine Life facilities  -11/27/2007
Howdy Bob!
Well you did say I could write you when I had a question.<smile> I just didn't tell you I have aloooot of questions. Hope I'm not bugging you too bad.
I have an issue with NO3 in my invert system here,
<Not unusual... in a wholesale setting>
and have found out that there are a copious amount of bio-balls that are in a very hard to reach place. They have not been cleaned in a very long time. I know there are differing opinions on whether or not these are a helpful means of filtration.
<In a changeable, large/ish facility with vacillating bio-loads... something like them... or fluidized bed technology is really a necessity. Must have something that can/will rapidly ramp-up to convert nitrogenous wastes. Unfortunately such mechanisms overdrive nitrification... resulting in excess nitrate>
I did read through your FAQs but did not find any situation that correlated with mine. I don't like them, personally, I have seen a great number of tanks in my maintenance calls that have been helped tremendously by their removal and subsequent replacement with live rock.
<Yes... this has been my experience as well>
I don't have any experience with such large systems like ours (8500)
<Yes... gallons...>
so maybe there is a reason I don't know about that keeps them here, but my suspicion is that they were just designed in the bio-ball hey-day.
<This is indeed the case. I was there for all the fits, retrofits of Quality...>
My question is this..should I a) Not worry about my around 35-40 ppm of NO3?
<Mmm, if it were me/mine... I would try to address, reduce this... Have you spoken w/ ChrisB re your concern here?>
b) Rip out all the bio-balls and replace with live rock? keep in mind the bio-ball chambers are highly inaccessible, being underneath the holding tanks.
<Yes, I know... requiring the dismantling of all above them. A pain in the keester>
I would be concerned with a drain becoming blocked with the live rock. c) Break down the tanks and just clean the bioballs? d) Remove the bioballs and don't add anything? or e) some really obvious solution that is staring me in the face that I haven't realized, which is why I contact the guru's A.K.A. You!
<IF there were room, I'd opt for placing LR in some large container (even pressurized like a big Tahitian filter or two) outside the existing... BUT if you're going to take the invert. system apart... the addition/replacement of the plastic media for the LR in part or en toto will likely be a good route to go... and last for quite a few years...>
Anyway, I have some pretty unhappy coral (but some very happy clams!). Help? Thanks...you're awesome and way cooler then a bristle worm - Niki
<Don't know... have seen some very gorgeous errantiate polychaetes in my time... Cheers, Bob Fenner>
to Bob
Hi Bob,
Thank you for your reply, and yes I spoke with Chris yesterday and he explained to me the need for bio-balls in a wholesale setting. Thanks again for your input. Niki Englerth :)
<Ah, good. BobF>

Nitrates and a cold water tank – 09/21/07
Hi,
<Hello Ross.>
A year and half ago, two students set up a 100 gallon, cold,
<approx. temperature?>
saltwater tank for my classroom as a project. Since those students have now graduated, I have inherited the tank.
<Nice. I will set up a similar tank in the future, too, in order to keep some species I see regularly in large subtropical-temperate systems.>
As a result, I'm not quite up to speed about all there is to do to maintain the tank. Currently, there is a Magnum 350 canister with Biomax, a protein skimmer, and, I believe they are called, bioballs (round, blue, spiky plastic balls). The tank had two scup and hake (along
with a few crabs) for a year. The nitrites and ammonia have been zero since the original cycling. Toward the end of the last school year, the nitrates started creeping up. I removed all the fish over the summer (just leaving two crabs) thinking that the bacteria would have a chance to take back control of the nitrate problem. Unfortunately, that didn't really happen.
I've now added a number of invertebrates to the tank because I want to use them in the classroom. The nitrates are really off the charts now.
<A number would be good…>
(nitrites and ammonia still 0 ppm). So I have a couple of questions:
1. If the ammonia breaks down to nitrite and nitrite breaks down to nitrate, what removes the nitrate?
<Anaerobic bacteria, but those primarily live in deeper sediments as well as inside of porous rock material. Anaerobic bacteria turn nitrates into gaseous nitrogen that leaves the system.>
2. What do you think created this problem?
< Nitrates are what accumulates when feeding the fish. Most proteins in the fish food are ultimately turned into nitrates. That’s no problem, can be handled.>
I can do a partial water change (which I have done) but it doesn't seem to get to the root of the problem.
<Of course regular partial water changes should be done in any tank (at least 5% per week), but a water change of 30% can only decrease your nitrates by 30%. As a consequence large water changes are expensive for marine tanks due to the costs of the needed salt. What you probably want is natural nitrate reduction (also known as de-nitrification). Possible options for you are (order of my preference in this case): DSB (deep sand bed), live rock (see below for more detail), a refugium with cold water algae, a small sulphur filter. Those can be combined. You also should optimise the output of your skimmer and clean it regularly. Some recommended reading:
http://www.wetwebmedia.com/nitratesmar.htm
http://www.wetwebmedia.com/nutrientcontrol.htm.>
3. Finally, one of the posts I read on your site said to use more live rock etc. But live rock etc. seems to be associated with warm water tanks, how do I go about getting it for my cold water tank?
<It’s not only bacteria that make the rock live. More recent studies come to the conclusion you also need all the other filtering organisms, critters like feather dusters and such to transport water inside the rock. Current and diffusion alone are not sufficient. Therefore, you’d need rocks from approximately the same temperature as your tank to have critters that can survive in the tank. I think most tropic critters would not survive, but that depends on the actual temperature.>
Do I need to add new Biomax?
<Am not a fan of such nitrate removers except for emergencies maybe. Of course new Biomax would remove nitrogenous compounds like nitrates, but it has limited capacity and if your nitrates are through the roof it will likely only help a short time until you need to get a new one.>
Can you simply buy the bacteria you need?
<Anaerobic bacteria will develop “by themselves” in an anaerobic environment. In contrast to nitrifying bacteria I think they are not sold in bottles.>
What can I do to reduce the nitrate levels?
<Hope the suggestion above help. I’d start with a deep sand bed (can be seeded with sand from the unpolluted sea) and some porous rocks (read about curing live rock) in addition to regular water changes.>
Any help would be appreciated. Thanks.
<Cheers, Marco.>
Ross.

Re: Nitrates and a cold water tank. Nitrates and a cold water tank, follow up – 09/21/07
Thanks so much for your quick reply.
<You are most welcome.>
Of course, after I sent the email I realized I should have told you the temperature of the tank and the number and amount of invertebrates. The tank does have a chiller. The temperature is around 66-68° F.
<Okay, thank you for the information. Tropical live rock creatures would probably not like these temperatures, it would be best to get sand and rocks at the coast.>
There are about 4 small sea stars, 5 brittle stars, eight hermit crabs, 3-4 sea urchins, one Asian shore crab, couple of snails. (there were some small sea cucumbers but I think they were eaten by the sea stars).
By the way, I live in the Boston area. I wanted the tank to be a close approximation of our coast so I could easily gather inverts and keep them for classroom use. For DSB (deep sand bed), should I just collect some sand from a local beach?
<Sand from an unpolluted beach is fine. While sand grains, which are coated with beneficial bacteria, and all sorts of tiny inverts are desirable, detritus is not. I would put a few pounds of sand in a bucket, fill the bucket with water, stir the sand, remove the dirty water and repeat until the water stays somewhat clear while stirring. In addition I would not add all the sand to your system at once, but prefer adding a few buckets at a time. Finally it would be good to aim for at least 4”/10 cm of substrate. See http://www.wetwebmedia.com/deepsandbeds.htm and the linked FAQs. Typically it will take some weeks until stable bacteria populations, that remove nitrate, have established in the anaerobic zones, but once the deep sand bed is active it can be very effective.>
When doing a water change, I guess I shouldn't vacuum deep into the sand bed as that might expose what anaerobic bacteria I do have to oxygen. Or am I misinterpreting that?
<You are absolutely right. Just vacuum detritus at the surface if necessary.>
I do have a little bit of macro algae (Chondrus crispus). I've only been leaving the tank light on for about 2 hours a day though. A year ago, when the light was on longer, we had a problem with undesirable algae growing. Remove the light, and the problem went away. Will more light help my nitrate situation?
<It could, if the Chondrus crispus is growing fast enough to compete with the nuisance algae for nutrition. I’m sure the invertebrates would enjoy more illumination, too. As soon as the nitrates are low again, chances are not too bad that nuisance algae grow is limited and a somewhat more natural lighting can be introduced.>
Thanks so much for the recommended reading. They were very helpful.
<Thank you for sharing your most interesting project. Marco.>
-Ross

Nitrates, canister, BioWheel – 07/26/07
Hello,
<Hi.>
I'm writing to you today, because I have a problem with nitrates in my tank. I have a 46g Bowfront that is currently a FOWLR setup. For filtration I use a Coralife 125 SuperSkimmer, 15w Gamma Ray UV Sterilizer and a Magnum Canister filter. I know high nitrates are stressful for fish and I'm also in the process of converting my tank to a reef, so lowering nitrates is a priority. Ammonia and nitrites are 0, but nitrates are 50ppm. The only fish in the tank are a harlequin tusk and 3 damsels. I believe the canister filter is the cause of the nitrates and I want to know if it is possible to run my setup without it.
<Yes, if your skimmer is working properly and you have about 45 pounds of live rock and enough current. I’d use the canister only for additional flow and mechanical filtration with easy to clean foam (needs to be cleaned often, at least weekly) and for carbon if needed. Carbon can be quite beneficial in a future reef setup.>
It keeps the water clear, but the constant maintenance of replacing the carbon is a real hassle. I was considering adding a double BioWheel hang on filter in place of the canister.
<Is possible. I’d prefer live rock, DSB, a small mechanical filter (if you really want to replace the canister) and, if possible, a sump or refugium, but it’s your choice. See http://www.wetwebmedia.com/nutrientcontrol.htm and http://www.wetwebmedia.com/marine/setup/filtration/biological/biofiltr.htm for further opinions. And don’t forget partial water changes to decrease the nitrates.>
My concern is that this will cause a mini cycle while the bacteria establishes itself on the BioWheel. What is your take on this?
<Can happen. Therefore, I’d add the BioWheel hang on (if you decide to use it) while the canister still is connected and can deal with unwanted nitrogen compounds from the BioWheel. Dirt from the canister can be used to seed the BioWheel.>
Thanks for reading, I'm looking forward to some great advice.
<Hope you like it. Cheers, Marco.>

Another DSB/Nitrate Reduction Question – 06/23/07
I have a 58gal tank + sump with approx 45lbs live rock, crushed coral substrate.
<<This last is likely a large contributor to your Nitrate issue>>
A Finger Leather, a few Mushrooms, Xenia, Zoanthids and some Yellow Polyps.
<<But for the Xenia, quite a noxious combination>>
All are small and well spread out.
<<But in a relatively “small” volume of water…do employ some purposeful chemical filtration (Poly-Filter/Carbon)>>
Livestock = Yellow Tang,
<<Tank is not big enough for this fish, mate>>
Maroon Clown, Royal Gramma and a Sixline Wrasse + Snails and Hermits.
<<Not that you should consider it now, but if things change, that Pseudocheilinus will make future fish additions problematic>>
Protein skimmer that makes about an 8-12oz of dark skimmate a week. My nitrates are consistently in the 20s.
<<Ah yes, this needs to come down. It’s hard to say for sure but, perhaps you need a better/more efficient skimmer>>
5-gal water change every 2 weeks with aged RO water.
<<Allowing the salt mix to “blend” for several days I hope>>
It’s understood that by increasing water changes, I will dilute the Nitrates, but I do not want to have to do this on a permanent basis.
<<Mmm, understand the mindset…but on this small volume this is an inexpensive and most healthful process. And doubling the volume to 10-gallons could make a very big difference here>>
Reduced feeding does not seem to help reduce the Nitrates.
<<Coming from somewhere else>>
It seems that I have a lot of debris in the crushed coral even after using a gravel vac.
<<Course substrates can be very problematic>>
I have taken some crushed coral out and cleaned it but I am afraid to do a lot at once for fear of shocking the tank.
<<Mmm…may not be much of an issue if the existing depth/volume is small>>
I think that a DSB is the way to go.
<<I am a strong proponent of this methodology>>
After the DSB is up to par I would add more live rock.
<<Don’t act too quickly re the rock…fishes need room to roam>>
At the present, 100lbs of pet store aragonite is not in my budget.
<<The retail side of the hobby IS proud of this stuff>>
I see 4 ways to get to my goal of having a DSB. 1) Remove all of the crushed coral at once and add a bag at a time of aragonite over several months until it reaches the 4-6 in. depth. 2) Add a 12x16x4 DSB in the sump inside a plastic container and then do the above. 3) Wait until I can get enough sand to do the change at one time. 4) Wildcard option, to use limestone play sand that I found in a local Home Depot (Chicago region).
It did pass the vinegar test, but it does not say where it is from. The pallet is in a slot marked Old Castle but I did not see Old Castle on the label, I can/will check again.
<<This is probably not Limestone but rather Aragonite sand…and most desirable/useful as such re our hobby>>
If these were your choices, what you would do?
<<Hmm, a combination of all these choices! I would purchase sand from Home Depot…add the DSB to the sump and wait a week…remove the crushed coral from the display and add the full depth of sugar-fine Aragonite to create the DSB… And do consider rinsing this sand before adding to the display. Some authors say this isn’t necessary…and on new systems it is less of an issue…but I speak from experience when I say you will not like the result if you merely dump this sand in to your existing display without rinsing away at least “some” of the “fines”>>
Until the nitrates are lower, I will not add anything and will have to increase the water changes.
<<Good>>
I consult the WWM regularly and am thankful to all of the crew for the comprehensive site.
<<The “Crew” is happy you find the site useful>>
I do not understand how you all have the time and patience to answer our repetitive questions.
<<Hee-hee! Can be trying at times for sure…but the greater good we “know” we are doing far outweighs the occasional inconvenience or thoughtless/selfish querier. And to be fair, the “Crew” has it easy compared to Bob who must “handle” all the queries we leave, as well as maintain the site/post all for the public’s edification>>
After reading your daily questions for a while, I have come to the conclusion that many of us who ask questions (myself included) are not ready to accept the hard truth; we want a magical cure to Ich and other problems, as in my case Nitrate reduction.
<<Ah yes! Tis true many write in looking for validation for something they know is wrong, and subsequently refuse to accept the “hard truth” as you say…but by far the majority of folks are just looking for some “personal” attention/guidance to their dilemmas. And as we often tout here…nobody should rely on a “single” source for their information anyway. Hobbyists should research/attempt to gain information from a variety of sources (books, NET chat forums, WWM, hobby clubs, etc.) and use their own good judgment to choose a course of action…WWM is just one cog on the wheel>>
Thank you!
<<Quite welcome…and “thank you” for this opportunity to rant [grin]. Eric Russell>>

DSB questions 6/6/07
Hi Crew,
<Ed>
Thanks for all your help so far. You've been an invaluable resource in helping this noob get started on the right foot.
I have a 42 Hex with 40 lbs LR, a 3 inch sandbed (mixed fine live sand and CC), 175 MH pendant, Remora skimmer on MJ1200, and a rio400 powerhead for added circulation cycling for 5 weeks now. What's in there so far is the cleaning crew (2 skunk cleaners shrimp, 1 sm. brittle star, various hermits and snails) and a couple small frags (few Zoa buttons, GSP, 1 sm Xenia stalk, 1 sm mushroom) and no fish yet. I do a once a week 5 gallon water change and top off with RO/DI water. Everything is doing quite well.
My question is about the sand bed. My nitrates have been sitting pretty steadily at 5-10ppm. I was concerned that maybe my sand bed is just a bit too shallow or coarse. Might this be the case?
<Mmm, yes... and your system is new...>
I've read that DSB's will perform differently depending on the situation and my tank is taller than it is wide, hence lower surface area. Can I add more fine live sand at this point without affecting the tanks cycle?
<Likely so, yes>
Would this even help?
<Ditto>
I did just add 10 Nassarius snails this week. Before that, nothing was really sifting through the sand which I realized after some research is quite necessary. Would more sand stirrers be beneficial?
<Not really>
I guess 5-10ppm nitrates isn't that bad and maybe I'm just being impatient, but I'd like to see them at 0 before adding any more livestock. Thanks so much for you time =D
Ed Gambler
<Mmm, will likely never be zero here... w/o the addition of more outside filtration of a few possible designs... I take it you have read on WWM re Nitrates and their control. Bob Fenner>

High nitrates – Proper skimming and natural nitrate reduction should solve the problems – 06/05/07
I live in South Florida and after hurricane Wilma last year I experienced 11 days with no electricity. For the first 3 days I had nothing and for the next 8, I had 8 hours a day of filtration thanks to my neighbours generator. Ever since that time I have been battling very
high nitrates.
<It might have been good to give specific numbers to work with.>
I have a 100 gallon tank with 75lbs of what I think is still live rock, 4 medium fish, some soft corals and a 20 gallon sump with a bio rocker filter. I have to get a new power head for my protein skimmer and I have not put my plenum back into the system loop. The protein skimmer has not been out of the system for too long but, I never really get a lot of output.
<Re-calibrate your skimmer or get another one if not possible to get better results. A good skimmer in a well stocked tank should produce at least 1 cup of waste per week.>
I recently did a 60 gallon water change and changed the sand with no help on the nitrates.
<It would have been good to know how high the nitrates were after the water change. I hope you used a water source free of nitrates e.g. R.O.>
My problem is I want to make the necessary changes to the tank to get it healthy again but I do not know where to start. Should I change the media in the bio rocker, add to or completely replace my live rock, do continuous water changes? I don't know what to do first, so that I don't make more problems.
<Improve protein skimming to decrease further nitrate production as much as possible. To decrease the already existing nitrates continue doing water changes. Macroalgae such as Chaetomorpha and/or a DSB in your sump or a refugium are a big help to keep them down, too. Personally I do not like or use wet/dry filters. See http://www.wetwebmedia.com/reeffilt.htm and http://www.wetwebmedia.com/nitratennr.htm .>
Please HELP! I want my fish and the rest of my tank to be safe and happy. Thanks, Robin
<Cheers, Marco.>

Nitrates reduction 6/4/07
Hello Bob and/or your fellow Crew members!
<Hello>
Again, thank you for the wealth of information you provide on WWM. I have learned so much from your site and can literally spend an hour a day reading and learning. Truly amazing the amount of information you provide and it is so appreciated.
<Lots of stuff here for sure.>
I have questions about Nitrate control. I have read your FAQ's on the subject and have learned a great deal of info, but am hoping you can give me some information specific to my tank. I am new to the hobby. I have a 55 gallon Hex (I know, not ideal, but it is the tank we had to work with). <As long as you are aware of your limitation.> No sump/refugium, and at the moment neither are an option. <There are decent hang-on-back models for refugiums if you are interested.> We have a Fluval 305 canister filter, a Bak Pak 2+R skimmer, and 3 power heads. Between the filter, skimmer, and power heads, we have approximately 750 gallons/hour of water being circulated. I know with a hex, the gas exchange isn't great, so I decided to have enough power heads to give me good water circulation. <Good> I have about 30 pounds of cured live rock and 20 pounds of base rock in the tank. I have a 2 inch substrate consisting of 30 lbs of sugar fine aragonite mixed with 20 lbs of Carib-Sea Arag-alive live sand. After reading on your web site, I realize this depth of sand bed may is either too deep (over 1 inch) or too shallow (under 3 inches) to aid in ridding the tank of nitrates. <Yep> That being said, I have a healthy population of copepods, amphipods, and bristle worms already established in the tank, and there is a good amount of some red macro algae growing from my LR.
The tank has been cycling for 2 months with no fish. <Good> For the duration of the 2 months, the ammonia and nitrite levels have remained at 0. Within the last 2 weeks, the nitrate levels have risen slightly to 5 ppm. I did a 5% water change last week, the first water change the tank has had as it has been cycling. Also added our first fish last week, a Midas Blenny. He seems to be doing well, eating well, has already found his favorite "nook" in the live rock but often swims about. What a great little fish he is. <Agreed>
Testing my water parameters yesterday, my ammonia and nitrites were still 0, but my nitrates had risen to 10 ppm. I am sure the addition of the fish, with the feeding and waste being produced is contributing to the higher nitrate level, but I am wondering what I can do to prevent if from rising even further. Based on what I have read on your site and in other literature, I know Midas Blennies like frequent feedings. I have been feeding him frozen Mysis and flake food in small quantities twice a day. <Replace the flake food with pellets, better for the fish and less release of nutrients directly into the water.> He seems to gobble up whatever I put in the tank, and acts as if he would like more food. <A sign of good health.> I am so concerned about overfeeding that I am being very conscious of the amount of food I am putting in the tank. <Good> That being said, I still wonder if I am feeding too much for this fish even though he "appears" to eat everything that goes in. <If it is gone quickly likely ok, 30 seconds to 1 minute to consume all the food.>
So my question is, with my set-up, tank limitations (no sump/refugium an option at the moment) LR and sand bed depth, livestock/feeding habits, what would be your recommendations to keeping my nitrates under control? I plan on 5% water changes every week, and my skimmer has started pulling much darker gunk from the tank since the blenny was added. Should I reduce/increase the depth of my sand bed? <Could, would be a good idea.> Any feeding suggestions specific to the Midas Blenny so he remains well fed without being over/under fed? (I looked for this info on the WWM but didn't see any info specific to Midas Blennies). Or is this just a case of my tank still cycling and me needing to demonstrate more patience? Any insight you could give would be greatly appreciated.
One last thing, I promise! :-) Every time I attempt to register to become a member of your site, I see a message that says registration is temporarily unavailable. I have received this message for the last month. I would love to register so I can post some of these questions on the message boards. Any idea when registration for new members will become available? <It actually a separately owned and operated site, but I'll send a note over to the mods there and see if they can take a look.>
Thank you once again for the reply. I really don't know how I could have come this far in the hobby without your insight, advice and support.
Jamie
<Nitrates take some manual work to get rid of. You could slowly add to your sand bed, maybe 1/4 to 1/2 inch a week. Either way clean your Fluval very often, weekly for sure, and move up your water changes to 10% weekly (5 gallons). This should help lower them, although I don't consider you in the danger area yet.>
<Chris>

Just when you think all is fine...WHAMMO!  Thirteen fish dead...  GFCI use, alcohol use (in denitrators mostly)   5/21/07
Hi Bob,
Not to solicit sympathy, but because I know you would care/be interested to know...
<Oh oh....>
A faulty GFCI (still investigating but this is where the finger is pointing) tripped sometime
<Do this... even go bad w/o any notice...>
after my last look at my tank on Saturday night and was not discovered until mid-morning Sunday while the tank was still dark when I noticed the drop in water level in the display.  This circuit happened to be the one my sump return pump is on.  By the time I saw there was a  problem and got the system running, twelve fish were expired and the remainder were in severe distress from what I have concluded was oxygen deprivation.
<... bunk>
  Normally with good circulation (the Tunze pumps) I would expect my tank to be able to maintain acceptable oxygen levels, but about an hour before the tank went dark the night before I had dosed 6ml of Ethyl Alcohol and believe the resultant bacteria boost consumed the available oxygen faster than water circulation could handle without support from the sump/skimmer.
<Arggggg! Am sure you've seen my rants re such feeder stocks to boost anaerobiosis...>
Of the initial survivors, the Yellow Tang never fully recovered equilibrium and died several hours after discovery.  Amazingly the Copperband Butterfly was/is still alive and is swimming upright but seems disoriented/confused, as well as light sensitive, and will not eat...not a good prognosis.  The pair of Orange-Tailed Damsels seem unaffected, as does the Dragon Goby.
The Yellow Wrasse (H. chrysus) is very active and appears to be swimming well but is not eating though it did show more "interest" in food than the Copperband.  But most surprising to me...the pair of Leopard Wrasse popped out of the sand bed shortly after the lights came on and are actively cruising, browsing, and ate well when fed!
<Thank goodness>
I can only guess the effects of oxygen deprivation would be much the same on the fish as it is on us/any animal, and only time will tell the full extent of damage.  Eric
<Yes... sorry to realize your travails. Socios miseris habuisse dolorem dicet. Cicero. BobF>

Re: Cleaner Shrimp Killer...Those Tangs Are NOT "Reef Safe" Fishes After All! - 05/22/07
Oh NO...I'm sorry to hear you had some tragedy with your system, Eric.
<<Thank you Linda>>
I hope someone was available to help you in some way as you are always available for people like me.
<<Nothing for anyone to do....  A faulty GFCI cut power to my recirculation pump overnight, resulting in the loss of thirteen fishes (375g reef display).  This alone would not have been problematic, but shortly before lights-out I had dosed Ethyl Alcohol to boost bacterial populations.  The resultant increase in aerobic activity quickly consumed the available oxygen once the recirculation pump was shut off and the skimmer was no longer providing oxygen-saturated water to the display...at least that is what I have surmised>>
Wish I could help...Linda (in very dry GA)
<<Your expression to do so is enough.  EricR...in similarly parched SC>>

R2: Cleaner Shrimp Killer...Those Tangs Are NOT "Reef Safe" Fishes After All! - 05/22/07
Eric, that is heartbreaking.
<<Indeed...a saddening event>>
I am truly sorry.
<<Thank you>>
When things that massive happen it tends to make me wonder whether we should have these precious items in our possession...but, then if you are like me, I LOVE the ocean and having a piece of it in my home is so gratifying and well appreciated, and never taken for granted.  So, what do ya do?
<<Mmm, even “small” losses are not to be taken lightly, but my best advice here...don’t let such events cause “knee-jerk” reactions...and above all else, learn from it - Cuiusvis hominis est errare, nullius nisi insipientis in errore perseverare.  Cicero >>
By the way, the guy I bought that nice, great big cleaner shrimp from that my Hippo Tang had for lunch, had just told me the story about his Hippo Tang and what a holy terror he has been in his reef tank and said he was going to have to find it a new home!
<<A more “common” occurrence with these fishes/Tangs in general than many realize I think>>
He said his Hippo Tang is ripping his fish apart.
<<Yikes!>>
Geez!  He said he really likes the fish, though, because when he had ordered live rock, the fish had wedged himself inside one of the crevices in only 2-inches of water and when he went to place the rock in one of his tanks, out came this little Hippo tang!  He couldn't believe how he survived.
<<Amazing...and further testament to just how sturdy many marine fishes truly are>>
I just discovered this guy’s new fish store.  It is beautiful and he only deals in saltwater.
<<Sounds like my kind of place>>
He has fish, all types of corals and invertebrates.  A really nice guy.  The store is located in Flowery Branch, GA, in north GA.  Everything, the tanks, the water, looked so clean and healthy.
<<Very nice>>
I will go back to him, for sure.  (I want his job!)
<<Hee-hee!  Tis LOTS of work!>>
Keep on going, Eric...Linda in GA
<<Never intended not to, Linda [grin].  Eric Russell>>

NNR and Hang on Tank Refugium   3/4/07
Dear Sir or Madam:
<Tim! "I am the knight who says, fish!">
Congratulations on running such a helpful website for us aquarium keepers!
Thanks a million!  My boys and I have learned a lot from you guys.
<Great!>
We have a 75 gallon fish-only saltwater tank with 80 pounds of live rock and about 15 fish of assorted varieties.  We have been running this setup for about six months now.  We have been plagued by excess nitrate levels.  We now have a RO filter for water changes and try to observe best practices, but we still do not have nitrates under control.  I am getting sick of expensive water changes (sea salt ain't cheap).
<Mmm, no... and tossing/switching it out is not always the best approach to maintaining good water quality...>
I think a deep sand bed in our main tank would be very expensive.  However, I am considering adding a hang on tank refugium for the sole purpose of NNR.
Is this practical?  Would it help?  How big should it be?
<Will help... bigger the better... Would like to see you situate a bigger "outside" (with pump...) one instead... Please read here: http://www.wetwebmedia.com/refughangonmodelfaqs.htm
and the linked files above... Bob Fenner>
Thanks,
Tim Swift

Deep Mud Bed for NNR...Yes   2/25/07
Quick question.  Could a deep mud bed help with NNR as effectively as a DSB.  
<Both deep sand beds and deep mud beds can successful reduce nitrates to zero more here:  http://www.wetwebmedia.com/nitratesmar.htm and here http://www.wetwebmedia.com/mudfiltrfaqs.htm also links in blue at top of pages.>
If the answer is no, my follow up question is why not.  Thanks a million.
<Welcome!  -Mich>
Ari

Nitrate Reduction Question, Confusion with Remote Deep Sand Beds and Natural Nitrate Reduction.  2/7/07
<Hello! Mich here.>
Just wanted to let you know that I use your site almost everyday to lookup answers to questions.  
<Awesome!>
On one of the posts for either DSB or Nitrate Reduction it was mentioned to take a 5 gallon bucket and place a Plenum in it and fill it with sand to create a nitrate filter.  A couple of questions I have regarding this; the way the mention made sound was to have the water inlet above the sand line and the water outlet above the sand line as well and let the water flow across the sand.  
<Correct.>
1st question is how much rate of flow should go across this; the tank is 125 with a sump and a 30 gallon refugium also with a DSB.  I figured I would run an additional pump to get the correct flow.  
<Minimal flow, a small powerhead should do it.>
2nd question is with the concern about the DSB becoming a nutrient sink, why wouldn't you let the water flow out the bottom of the plenum bring the water flow faster through the sand?  This would then prevent a build-up of the nutrients; wouldn't it?
<No.  You are thinking on a macro level, for this you must think on a micro level.  Think biological filtration not mechanical filtration.  The point is keeping the deeper areas of the sand anaerobic or without oxygen.  This helps in nutrient breakdown, a means of NNR Natural Nitrate Reduction.>  
Thanks
<Welcome!  Hope that helps.  -Mich>
http://www.wetwebmedia.com/nitratennr.htm
http://www.wetwebmedia.com/dsbdepth.htm
http://www.wetwebmedia.com/denitrification_erfaqs.htm
Cary Meredith