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FAQs on Marine Freshwater Quality involving Nitrates: Control

Related Articles: Nitrates in Freshwater Aquariums, Establishing Cycling, Freshwater Filtration, Know Your Filter Media, A Concise Guide to Your Options by Neale Monks, Setting up a Freshwater Aquarium, Tips for BeginnersWater Quality and Freshwater Aquariums

Related FAQs: Nitrates 1, Nitrates 2, & FAQs on FW Nitrates: Importance, Science, Measure, Sources, Chemical Filtrants, Troubleshooting/Fixing, & Ammonia, FW Nitrites, Biological Filtration, Freshwater Nutrient Cycling, Establishing Cycling 1,

Short term: Dilution with new water (changing out for old) that is treated to remove sanitizer.
Long term: Establishing and sustaining sufficient denitrifying bacteria in a stable, aerated setting. Mmm, more filter media, perhaps substrate, less feeding, more gravel-vacuuming, use of chemical filtrants... Use of live plants, denitrification areas.

High nitrate levels in pond and aquarium       4/18/20
Hi Bob and Friends,
<Hello Annette.>
Recently my platys have been dying. All my other fish seem ok. I did a water test kit from API and the pH was 7.6, but the nitrates were at 160 ppm, which was the highest level.
<Yikes! That'd be the reason. Fish vary in response to nitrate. Cichlids and Mollies are very sensitive, and long-term, anything above 20 mg/l can cause health problems. Most community fish will be fine up to 40-50 mg/l, and characins and catfish seem to be, on the average, among the least sensitive fish (which probably explains why they were old favourites for community tanks up to the 1970s, when people avoided water changes).
Platies are likely to be more like Mollies, so your high nitrates could easily be the problem.>
Is there anything I can do?
<First up, a water change. Do a series of changes across the next few days, such that you change 30-50% of the water each time. Try and keep water chemistry and temperature steady. After a few days, nitrate should be close to whatever your tap water level happens to be. Secondly, review stocking, tank size, and feeding. The old rule that says "an inch of fish per gallon" is pretty good, so if you had, say, 10 platies, these are about 1.5-2 inches long, so you'd need 15-20 gallons to keep them. Any additional fish would be added to that, so if you had, say, six Corydoras catfish, each about the same size, they'd be another 9-12 gallons, so together your tank would need to be at least 24-32 gallons in size. This rule is conservative, but works really well for small fish in the 1-3 inch size range. Feeding should be moderate, and as a rule of thumb, small community fish need a 'portion' of flake about the size of their eyeball each meal. Feeding once or twice a day is fine, and for fish like Platies especially, just letting them graze on algae (or softened vegetables, such as spinach, peas or
cucumber) is a fine way to round out their diet. Overfeeding fish doesn't kill them by poisoning them or blocking their stomachs or something, but too much food does mean the filter is working harder, and as you can see, the end product of filtration, nitrate, isn't non-toxic. That's why we do water changes every week or two: to dilute that nitrate. Fast-growing plants (such as floating plants if you have indifferent lighting) can be really helpful too, since plants absorb nitrate.>
The pond was the same. I saw a De-nitrate water additive.
<Don't waste your time with additives. Water changes do a massively better job, for much less cost. Honestly, while there may be niche applications where denitrification is relevant to freshwater fishkeeping, there's otherwise no reason to get bogged down in this side of things. Instead limit stocking, ensure the tank is nice and big, don't overfeed, and do regular water changes. That's all you need to do, and it not only works well, but doesn't cost anything!>
<Cheers, Neale.>

Sulfur Reactor in FW (Bob, bit out of my zone here -- anything to add?)<<>>   10/6/10
Hi There,
I have a 190 Litre cichlid tank which is about 12 months old. This is completely plant less and has had high levels of nitrate and has always had algae problems.
<I bet.>
Until recently I used a sump as an algae trap which helped a lot but decided I would give a sulfur reactor a go.
I emptied the sump, filled it with crushed coral and bought a sulfur reactor and dosing pump. The pump takes water from the front of the sump, runs through and then comes out onto the coral.
My tank has been 0ppm amm, 0ppm NO2, 40-60ppm NO3 since matured and is still currently sat at these readings.
I have had the dosing pump putting water through as 1200ml per hour as this is the lowest I can get it to go, its a 12v motor running at 3v to slow it down.
The readings from the effluent are 0.5ppm NO2 and 20ppm NO3, it has been up and running for a week now with those readings since day 1.
<<RMF would let the system cycle before turning on the reactor>>
 pH seems to be fine and has been at 8.2 since adding the coral and running the reactor. I am wondering if I need to try and either slow down the flow further or if I should put a long piece of tubing in front of the reactor to try and create a coil and remove the O2 before it gets to the reactor?
<You might, but I don't honestly believe this is going to be the solution.>
If maybe I need to just leave it a bit longer to mature more before doing anything?
I have been looking over the internet to try and find help on existing topics but couldn't find anything conclusive. Thanks in advance for you help.
<Nitrate is notoriously difficult to control in cichlid tanks. It's not like a marine aquarium where you have light stocking, live rock, and minimal food input. In a cichlid aquarium the tendency is towards heavy stocking and generous feeding. To be honest, any nitrate-removal system in a cichlid tank will be overwhelmed. Put simply, nitrate removal systems work at levels of single milligrams per day, while your cichlids are cranking out nitrate at the tens of milligrams per day. Plants tend to work better than denitrification systems because their growth rate can be spectacularly high, especially in the case of floating plants. A sump filled with Indian Fern under intense lighting would work very well, and in many ways comparable to the use of Chaetomorpha in marine aquaria. Plus, Indian Fern is edible, and many cichlids enjoy it, so surplus can be used to feed Tropheus, Severums, Mbuna or whatever cichlids it is you're keeping. Anyway, with fast-growing plants of some sort you do tend to find nitrate stays manageable more easily than any other, and algae problems decrease the happier your plants are. Cheers, Neale.>
<<Mmm, such reactors can work in FW systems, but I do agree w/ Neale re other means... Again, DO turn off this reactor till the system is fully cycled... and read the article by J, the joker Charlie Delbeek here: http://www.fishchannel.com/saltwater-aquariums/aquarium-care/sulfur-reactor.aspx?

Deep substrate to lower nitrates in sump.    8/7/10

<Hi Richard,>
I have a 75 gal tank with a Firemouth, Convict, and 5 Tilapia. I have an Aqueon model 3 sump configured with a refugium and a 980Gph pump which returns to an under-gravel jet system covered by 3" of crushed coral. I simply cannot keep up with my nitrates. Weekly water changes still leave nitrates over what test kits can measure. After reading your DSB articles, I was thinking that such a thing just might be a solution beyond building a nitrate reactor.

<It is one option.>
The problem is that I'd have to completely re-build my UG Jet system to accommodate 5"+ of substrate (the jets would be under the substrate). This would require tearing down the tank (it's siliconed to the bottom), and I don't have the facilities do house the fish should I attempt this.

<Probably not the best solution then.>
Do you think that putting 5 or 8 inches of crushed coral or sand in the refugium would work in my case instead? Or is this too little to have an effect?

<Is the refugium in the 3rd chamber of the Aqueon 3?>
Right now I have some plants and moss balls in the refugium, but no substrate.

<While a deep sand bed is an option, it isn't always the best solution. Some people have great results with them, others no results at all. A plant filter which uses natural sunlight, or a few hundred watts of HID lighting is my recommendation. Plants eat nitrates. It is the perfect symbiosis.>
Thank you, Richard

<Hope this helps, Scott T.>

Re: Deep substrate to lower nitrates in sump. FW   8/8/10

Thank you for the quick and helpful reply.
The refugium is the 2nd and largest of the three chambers, in the middle.
It has 11 inches of water depth and has T5 lighting fixture designed for it. That is no where near a few hundred watts of HID though (might melt the clear cover).
Can you recommend a replacement fixture and plants that are voracious nitrate eaters? The flow rate in the refugium is enough to keep moss balls juggling around gently, so that is probably a factor.
<Maybe the best approach is three tiered. Try a deep sand bed, fast growing plants, and make sure to remove as much particulate waste as possible.
Is this the sand bed article you referred to?
I would follow it's directions for installation of a sand bed in your refugium. Then put some plants in that are fast growing. Lemna minor, Limnobium laevigatum, and Hygrophila are a few. Or any fast growing plants you have access too or success with. To light these a DIY 150watt HPS would work. Or something like a Current Sunpod model 1058. It is a somewhat small area, so the plants alone will not be able to keep up with the nitrates themselves. The combination of a DSB, plant filter, and well used filter bags should do the trick.
My favorite option for filtering large freshwater bio-loads is Aquaponics. If you are inclined, it is a wonderful symbiosis.
http://en.wikipedia.org/wiki/Aquaponics >
Thanks again for the input.
<Thanks for contacting us. Keep the questions coming.>
<Scott T.>
Re: Deep substrate to lower nitrates in sump.  8/8/10
Hello Scott,
Actually, this entire setup is for Aquaponics!
<Too funny, go Aquaponics!>
I just haven't started the grow beds in the grow tent (secret Jardin with a 1000w HPS, reflector, blower, etc) because the waste heat is too much for my air conditioning. I live in an apartment in Manhattan. I was sorely
disappointed when I fired everything up once I had it built.
<Darn summer heat. I had to shut down my indoor setup for the same reason.>
I have three aeroponic style beds plumbed to the return pump of my aquarium sitting in the dark grow tent waiting for the fall. I will be growing tomatoes and salad greens. I am not sure if I'll harvest the Tilapia though I have kept them on a certified organic feed that aquaculturists use.
<I did a similar thing with Koi.>
Anyways, thanks for the input. Especially the plant names and the link.
<I'm not certain, but I bet tilapia can deal with high nitrates. My nitrates were always a bit elevated with the Koi-aquaponic system. As long as you keep the pH reasonable with water changes, and ammonia is minimal, you should be all set. What are your water changes like? I did ~30 gallons a week on a 120 gallon system. The nitrates were always crazy, but the fish and plants grew like crazy too. For me less than 25% a week, and the fish suffered. It is also highly dependent on feeding. When not growing vegetables, reduce your feeding rate. If I fed the Koi as much as they wanted to eat, I would have had to do 25% water changes every day to keep things in check.>
<Scott T.>

Nitrite and Nitrate Problems
Controlling Nitrite and Nitrate Problems  10/15/09

Hello Chuck, I got another question for you concerning the same 30 gallon tank. We for a little while have had a problem with ammonia being really high, so we started doing 50% water changes like every 3 days or so but only vacuum the surface of the gravel so we don't disrupt the biological filter. The good news is the ammonia level is good now however our nitrites and nitrates are off the charts. Question is should we continue to do the water changes to bring these levels down or is there some other way we can bring these levels down to a safe reading? The fish seem to be happy and are very active, we are just concerned about these levels being harmful.
Thanks, John and Anika
< The good news is that the nitrites and nitrates are less toxic than the ammonia. I would watch the amount of food fed each time. Remove any uneaten food after 5 minutes by using a siphon. Clean the filters often
too. Plants will remove some nitrogenous wastes if they are healthy and the lighting is strong. Using Dr Tim's One and Only will help quicken the process. One you u are dealing with just nitrat4s then you can try to control them with water changes and try to keep them under 20 ppm.-Chuck>

Nitrate/baby guppy problem 05/29/09
Hi Crew, it's me again....
We have a nitrate problem in our 28 gallon.
<Nitrate is best removed from freshwater tanks simply by [a] not overfeeding the fish; [b] not overcrowding the aquarium; and [c] doing more water changes. Fast-growing floating plants are also good at using up nitrate, but that should be viewed as a supplement to frequent water changes, not an alternative.>
Our ammonia is at 0, nitrite 20 mg/l, nitrate 40...so the pet store recommended a bacterial supplement that claims to be 'for fresh and saltwater aquariums'. Will this work?
<No. Nitrate is broken down by anaerobic bacteria, such as those that live in live rock (in marine aquaria) or stagnant mud (in ponds). It is not easy to create these conditions in a freshwater aquarium, so denitrification (the breakdown of nitrate to nitrogen gas) rarely takes place quickly enough in freshwater tanks to make any difference.>
We have a male Betta, my only remaining Neon Tetra, 3 Glo-Fish, 3 Giant Danios, and an African Dwarf Frog. Our 10 Ghost shrimp and 5 Mystery snails all died...and my Betta, who used to easily eat 20-30 pellets (!) a day, now only gets 4 or 5..those giant Danios...:)But anyway he's usually a bundle of energy and now he's lethargic and fights with his own reflection.  Plus his eyes look clouded. We got him almost 7 months ago so could these be age-related cataracts? And my baby guppies (they were born on April 7th) are in the 2.78 L, there's only 2 of them and both look pregnant. One just died...so should I move them to the 28-gallon in a breeder net with our nitrate level?
<I can't see Guppy fry doing well in 2.78 litres of water. Seriously, that's not an aquarium; it's a soda bottle.>
Yes, we have live plants-Umbrella, Amazon Sword, Peacock Fern, Aqua Fern, and White Ribbon. The Amazon Sword ones-and only those ones-are dying. Why?
<Probably not enough light. Umbrella Plant (Spathiphyllum wallisii), Peacock Fern (Selaginella willdenovii), Aqua Fern (Trichomanes javanicum) and White Ribbon Plant (Dracaena spp.) are all non-aquatic plants that will die kept underwater within a few months. Any retailer who sold you these was CONNING you out of money. So I wouldn't trust him/her on anything.  There are many retailers who sell these plants to inexperienced fishkeepers. These plants ALWAYS die and NEVER last for long underwater.  Total waste of money. The reason they "look" healthy is that their leaves are stiff, being adapted to living on land where gravity is more of an issue than underwater. So it takes a long time for them to look dead. But
DIE THEY WILL. Take them out, put them in houseplant soil, and stick them on a windowsill. Enjoy them for what they are: houseplants! As for your Amazon Sword, these are demanding plants that need strong lighting (at least 2 watts per gallon, ideally 3 or more watts per gallon) and a rich
substrate containing iron and other minerals; plain gravel will not do!  Usually when people fail to grow these plants, it's because [a] there isn't enough light; and [b] they stuck the plants into plain gravel without considering their need for fertilizer.>
Please help...
<Cheers, Neale.>

The game plan. FW maint.  - 9/3/07 Neale, <Kristi,> All right, hours of reading/research on the WWM site and your expert advice resulted in the following game plan to address my issues. Could you please review and confirm that I'm not missing anything. <Will do.> 1. Initially add sea salt (@ 1 gram per liter) for short-term detox of high nitrites. I'll use this only as needed for spiking nitrite levels. <Yep.> 2. Feed only once per day for now, <Correct.> 3. Hold off on gravel vacuuming, <Do, don't do; it really doesn't make much difference. I find hoovering up the detritus with each water change is easier and less likely to uproot the plants.> 4. Add more gravel substrate (I currently only have 1 inch), <Depends on what you have in the tank. If no rooted plants, then 1 inch is fine. Too much, even. You only need enough to cover the glass, and volume used for gravel is taking away volume of water. And the more water, the more stable the conditions in the tan. Lots of plants don't need gravel and prefer to grow on objects (rock, wood) for example Anubias, Java moss, and Java fern. On the other hand, rooted plants need about 3-4 inches. To some extent rooted plants (like Vallisneria, Amazon swords, etc) also need nutrients in the gravel too. I use pond soil, but others use laterite or fertiliser pellets they shove into the roots of each plant every couple of months.> 5. Replace current power filter with BIO-Wheel (I changed out the carbon filter three days ago before realizing I was throwing away the good bacteria - oops) <OK.> 6. Add BioSpira to help establish good bacteria more quickly. <If you want. At this stage it probably won't make a massive difference, because you have half the bacteria established already. But it won't hurt. Follow the instructions on the package carefully.> 7. Consider adding a small bubble wand to add more oxygenation (although I already have a bubbler water feature along with the power filter serving up to a 20 gallon tank). Would the ADF be ok with more water current, or should I hold off on the bubble wand? <Ah, should be fine. But as I've said elsewhere, frogs and fish don't really mix. Frogs (generally) live in still or stagnant water where fish are unable to live. They can't compete very well in the wild -- fish simply eat frogs because they swim so much better. So to some extent this is a "suck it and see" situation; try it out and see what happens.> 5. Hold to weekly 50% water changes unless levels become dangerously high. <You can't do too many water changes, so be flexible here. Provided the new water has zero ammonia and is of the same pH, hardness, and temperature as the old water, do as many water changes as you can.> 6. During water changes, treat "new" dechlorinated water with Ammo-Lock as well to address Chloramine issues. <Yes.> 7. Eventually decide on algae control critters, but don't add until tank stabilizes. <Algae control critters are a contradiction in terms. Adding animals to an aquarium increases the nitrates and phosphates, which increases the rate at which algae grows. Biology doesn't care if the animals eat algae or fried chicken, all animals are pumping out nitrate and phosphate. The only algae control that works is adding fast-growing plants. Vallisneria, hornwort, Cabomba, etc. Somehow, for reasons not entirely clear, these plants suppress the growth of algae, to the point where it stops being a problem. It sounds bizarre, but truly, you can have an overstocked tank but if there are lots of plants in there, at most you'll be wiping a little bit of algae off the glass once every six weeks. Quite how this works isn't clear, but it may be something to do with allelopathy, the ability of plants to (effectively) poison algae so that their leaves stay clean. There's so much about plant physiology we don't understand, but this is one aspect we can put into use in the aquarium.> Hmmmm...anything else? Oh yeah...more patience. <Hah!> This fish thing is becoming addicting!!!!!! Thanks again to you and the WWM site for all your guidance and info. Kristi <Happy to help, Neale>

FW filtration, lowering pH though using Aragonitic mat., and NO3s in an Af. cichlid set-up   6/20/07 Hey guys. In your opinion, regarding freshwater tank setup, do you think it would be equally as effective to put two Aquaclear 500 HOB filter on a 125g opposed to one canister and one HOB Aquaclear 500? <Mmm, possibly... though I would in either case, locate the units at either end of the system, clean only one per week during other regular maintenance... water changes, testing...> I am setting up a tank for a friend and through my past experience I really think that the HOB's do a better job at filtration. Currently on my 75gal I have one of each (canister/hob), what do you recommend for a large tank like this? <For what sorts of livestock? If this were a planted tank, I'd opt for the mix of units... for Af. et most Cichlid set-ups the two outside power filter hang-ons if these were my only choices> Also, on my Malawi tank I put roughly ten pound of crushed aragonite as my substrate to buffer the ph. <Good> In the beginning, my ph was steady at about 7.9-8.0, now i notice that it has gone down to about 7.5-7.6, what could be the problem? <The more-soluble parts/faces of this substrate are gone... a good idea to refresh (replace, add to) occasionally... every three months or so in this proportion of sized tank/gravel> Also, my nitrates are constantly at 40ppm even shortly after a large water change on my 75gal. <Too high... a good idea for you to read here: http://www.wetwebmedia.com/FWSubWebIndex/fwmaintindex.htm See the yellow tray, Nitrates below?> My bio load is only at half of it's maximum plus the fact that it's well over filtered with filtration rate of 850gph. I have about ten cichlids and one catfish with a total of about 40 inches so I guess I probably have about 30 more inches left to stock (going by general rule of thumb....1" per gallon). Any ideas as to what may be the problems here? <All sorts> Thanks in advance for your time and help!!! Jason <Read on my friend, read on. Bob Fenner> Re: FW NO3   6/20/07 Thanks Bob. The link you gave me in the last email was targeted toward saltwater (even though it claims to be freshwater nitrates), <Ah, yes... we don't have enough mat. as yet to separate. Many of the principles apply to both...> and did not answer my questions. The article told you "generally" about nitrates with no information pinpointed to my current situation. I also checked the FAQ's and no one seemed to have the problem I have without probable cause. I have no probable cause, so with your several years of experience do you have any idea what the problem may be? <Yes... a simple balancing of a series of variables/equation... More food, metabolism on one side... not enough anaerobic digestion by certain groups of microbes on the other... And insufficient nutrient export otherwise... Again... please do re-read where you were referred to... the linked files at top.... Your options are simple to delineate... less food, esp. of a proteinaceous nature, less livestock... more anaerobiosis... DSB likely, perhaps specialized media (e.g. sintered glass, ceramic beads/macaronis... made for this...) and the export... more water changes, the use of chem. filtrants, purposeful photosynthesis... the DSB, plants likely in a tied in live sump... All gone over and over on WWM...> I vacuum once every two weeks along with 20% water changes. My bio load is only at about half of the maximum it should be <... not useful thinking... Try covering your "good eye" with your hand, walking backward for a minute... Really> for a 75gal tank. I have an Aquaclear 50 HOB and a Filstar XP3. I have bio rings and stars in both filters but no BioWheel so the bio filtration is constantly under water with no air hitting. I use no supplements and feed very lightly. So clearly Bob, can you see any probable cause here? I don't, I need help. Jason <Read my young friend, read. RMF> LOL, thanks for answering my simple question Bob. <Welcome... RMF>

Nitrates in a Discus tank.    12/26/06 Hi Crew, <Ari>     My discus grow-out tank is a 125 gallon w/ all-glass mega sump model 4 below.  My nitrates are too high (can be over 40ppm depending on day of week) probably from lots of high-protein foods.  I do a lot of water changes, but wonder if I should adjust my setup to help deal with nitrates.   <A good idea>     It is a heavily planted tank with plenty of stem plants, swords and Glossostigma, Riccia, and java moss ground cover. Have pressurize co2, 500watts of lights on tank, reverse photoperiod an 50 watts below, 2-4 inches of Fluorite main tank with undergravel cable heater, about 4 inches of freshwater miracle mud in sump, I left bio-balls in the sump.  I also just added water lettuce and hyacinth to sump (read an article on this website suggesting this). <Mmm, these last two re really too cold-water plants to be used here... I'd try other tropical species, lighting here... on a differing, though over-lapping light cycle with the main tank>    I don't vacuum substrate because of ground cover plants.  Do you have any suggestions to help me lower nitrates besides cutting down feeding, and more specifically, do you think I should a) rip of ground cover so that I can siphon gravel better, <I would not> b) should I add more Fluorite, miracle mud, or another type of substrate and <I would do this> d) should I remove bio-balls?   <Yes...>     All advice is very much appreciated. - Very truly yours, Ari. <And in the meanwhile "kick up", increase the frequency, amount of water changed... daily if need be. Bob Fenner>

Nitrate & Nitrite in an Uncycled FW Tank - 4/24/2006 Hi <<Hi Gary.>> I was hoping you could help me. <<I'll try!>> I have got a nitrate/nitrite problem.  I have recently started a freshwater fish tank.  Everything was going ok, took the advice of where I bought my tank, read up a few books, and I set the tank up. <<Many fish stores are less than properly educated.>> Then added the water with a water conditioner also bacteria, I left it a few days then added plants and rocks. <<If you added live bacteria, like Bio-Spira (anything else available is dead bacteria at best), it will have died in a day or so without ammonia from fish waster to feed it.  You add your fish right after adding the Bio Spira to your filter.>> I then also left a few days longer approx 4 days, after checking ph levels, ammonia, nitrate, nitrite, calcium hardness and carbonate hardness all seemed to be ok. <<You didn't read ammonia, nitrite or nitrate because your tank hadn't yet started cycling.>> I went and bought my fish a couple of days later and I noticed most of my fish had white spot so I treated that problem with tri sulfa tablets (treated twice).  This is when all my problems now have started the ammonia nitrate & nitrite levels went sky high so I started to do the water changes.  I have now just got the ammonia level down to 0ppm but the nitrate & nitrite are just getting worse. <<Your tank was not cycled, and now is.  Do daily water changes of 75% or more to keep these toxins down while the nitrifying bacteria grow in your filter.>> I suppose you can tell from this that I am inexperienced in aquarium keeping, but I do enjoy fish keeping.  I hope you can help me with this problem, as I am getting more worried about loosing my fish.   <<Keep up with the water changes, and your tank should be cycled in a few weeks.  Read on WWM to learn about fishless cycling for the future.>> I look forward to hearing from you soon Thanks, Gary <<Glad to help. Lisa.  In the future, please capitalize your I's and run your email through a spelling/grammar checker.>>

Re: Freshwater Tank Won't cycle... sump des., Denitrators...   3/28/06   Well, everything is still all well, except the 10 gal tank we are using for a sump seems to have sprung a small leak.  Since I've been needing a good project, I'm looking at this as an opportunity rather than a hassle. <Good attitude> I went out and bought a new 10 gal tank, and some Plexiglas.  This time I am sectioning off different parts of the tank to do different things.  All similar to what is going on now, but hopefully incorporating what I've learned in the past several months and do it better. I now have the left 5 inches of the tank filled with bio-balls, which fill over into a slim area where the external pump will get it's intake from also where I will put bags of Purigen, etc...) past that there is an area about 6 inches high and about 8 inches long, that I hope to fill with mud from the lake we live on.  The last 4.5 inches or so from the aquarium hold an enclosed fluidized sad bed filter that is powered from a little RIO that sits in the area where the Purigen bags are.  I inject air into the Rio to add more oxygen to the fluidized filter. I'm still running the denitrator, and just got a cheap dosing pump for it to feed it nutrients for a few min.s daily on a timer, and that seems to be doing OK for the moment, <Danger Will Robbins!> but ideally I would like to deal with it another way. <Mmm, need something like a pH, RedOx, DO meter, solenoid... to shut off the effluent should there be trouble...> I'm hoping with the 5 in deep mud bed, that there will be enough anaerobic bacteria doing there thing to deal with the nitrates. <You'll see...> I'm also putting in a 40w grow light over this whole system to encourage algae to grow is this part of my sump to better deal with phosphates, etc... What I was wondering is if you think this will be enough, and if you had anything you would recommend other that algae to put in there that would grow in the mud and do a good job at eating nitrates and phosphates, or any medium that would be best to have a lot of algae grow on it. <Don't know what sort of life, water quality... you have, otherwise intend...> Algae in the tank is not a big problem, and a few stingray Plecos do a great job of keeping the tank clean. thank again, -ed <... some grand experiments now! Bob Fenner>

High Nitrates In a Big tank  - 03/12/2006 Greetings from New York to the WWM Crew: I have been running a 72 FO FW for 5 years. Current stock is: Oscar 9", Snook 7", Dempsey 5", Convict 2", Rope Fish 5", Pleco 4".  Filter is a DIY wet/dry with bio balls at 300 gph. The Pleco and rope fish are new additions, and since their introduction nitrates have sky rocketed to 100ppm.  I feed only once a day but unfortunately I must slightly overfeed since most of the fish are afraid to compete with the Oscar for the cichlid sticks floating at the top, typically the others wait mid tank for the sticks that are pushed down by water flow.   I have tried sinking pellets but they don't take, the only food they like is floating sticks. Anyways after reading through a lot WWM advise I've come up with several ideas of how to deal with the problem long term, other the frequent WCs. First would be to add another 10g tank to the sump and plant it since planting the main tank would not be such a good idea with my stock.   Eventually moving some plants to the main tank as they out grow the nursery. If you think that this is a good way to go could you please recommend some hearty plants that wouldn't require a CO2 setup and too much extra lighting, I've read that nana's do alright w/o CO2. <When you feed the sticks and wait for them to sink, the filter is catching  many of them and adding to the problem. The Pleco is stirring up the gravel and I suspect much of the uneaten "dust" food that has settled in between the pores of the sand or gravel. Try soaking the sticks so they sink right away and then feed on enough so that all the food is gone in two minutes once each day. When you do your water changes I would recommend using a Python water changing system and gently vacuum the junk in the gravel. Make sure that you clean your filter weekly. You filter only collects waste, it does not remove it from the system. You have to do that. Anubias nana is a very easy to grow plant but it really isn't an effective denitrator because it grows so slowly. The best plants are the ones that grow very quickly . Amazon swords would help but may not keep up with system you have.> Second would be to add some sort of sintered glass or other denitrating media to the wet dry.  The ease of this approach is tempting but I have doubts whether it would be effective enough on its own.  However I am already in the process of updating my wet dry from a 1 stage to a 3 stage to accommodate a mechanical and chemical filters in the first stage.  It would be relatively easy to design the third stage for some sort of denitrating media.  If you thing this is worth while would lowering the water flow through this stage would aid in the denitrification process as some products like de nitrator require less then 60 gph. Thanks in advance for your help, keep up the good work, Matt < Depending on how high the concentration of nitrates are I would think that this media would be quickly exhausted and its effects would be temporary.-Chuck>

High Nitrates FW - 01/12/2006 High nitrate levels, I have an established tank that I have had for about 6months now. My nitrates are sky high, I have an underground filter, with a carbon cartridge. My ammonia and nitrites are 0. My question is how do I fix this, I see other comments to get live plants which I do not have but what kind of plants are best? Do I get them at a pet store or elsewhere? Is the filter a problem? Do I need to get another kind of filter? Oh I have 2 red Serpae tetras, 2 red eye tetras, one dwarf Gourami. I just added today a baby Chinese algae eater and 2 great Danios. This is when I found out about the high nitrate levels. Thanks for your help. < You probably have a lot of mulm in your gravel. It needs to be removed with a gravel vacuum. Next water change vacuum the gravel until the water runs clear. You should be able to control your nitrates with routine water changes and periodic vacuuming after that. Stem plants with good lighting and CO2 injection are the best nitrate removers. Plants usually don't do too well with undergravel filters.-Chuck>

Nitrate Removal  - 2/21/2006 Thank you for your reply, I'm very grateful. I'm going to the store right this movement. Also, in case the nitrate is high, how do I treat elevated nitrate readings ? Sincerely thank you again, Godfrey D'souza < In the aquarium the are taken up by plants like algae. The can be diluted by doing water changes.-Chuck>

Too Good to Be True! No Nitrates!   1/11/06 http://aquaripure.com/ I found this site, and I was wondering if this I a scam.  I assume it is because removing nitrates is a lot more involved than that for a marine aquarium right!? <The website information is accurate and has a lot of good information about nitrates and how to get rid of them. Here is how it works. Aquarium water is pumped through a long tube. Bacteria that live on the walls of the tube break down ammonia and nitrite into nitrates. When the oxygen is depleted by the aerobic bacteria in the tube then anaerobic bacteria grow and break down the nitrates into nitrogen gas. There is no oxygen coming out of the pipe but nitrogen gas and water. These keep coming up from time to time. They are expensive and in theory will reduce nitrates. The question is can they reduce enough nitrates to skip water changes? Many manufacturers in the tropical fish trade are aware that changing water is the least favorite part of fish keeping. There are chemicals for binding up nitrates, as well as chemical and biological nitrate removers on the market too. To date the most effective sure fire way to remove excessive mineral/nitrate build-up in the water is by doing  water changes.-Chuck>

Anaerobic digestion/Denitrator product input, Ariids in FW  1/8/06 Hello WWM crew. <Howdy> I have a few questions I can't seem to find the answer to. 1. http://www.aquaripure.com/index.htm this is the link to a filter that reduces nitrates in the water. Does this filter really work?   <Mmm, "can" but almost always doesn't is the fairest answer... folks don't keep up with feeding (a source of ready carbon, usually a sugar, sometimes an alcohol) to these units... and the claim re cutting back on water changes... fallacious is a nice adverb here> 2. I have a 30 gallon tank with a 1-redtailed barb,1-silver-tipped catfish and a 1-peacock cichlid. I know that the silver-tipped catfish needs to eventually be in brackish water. Will the silver-tipped catfish live his/her life span in freshwater conditions? <Mmm, a much fore-shortened one... the answer, no> 3. In the same tank as described in question 2, I am running two Marineland Emperor 400 power filters. The entire tank is recycled about 26 times per hour. Is this too much water current for the fish? <Nope> Thank you, your time IS greatly appreciated by all <Welcome. Bob Fenner>

Getting High Nitrates Down  12/26/05 Thanks Chuck. I'm still slightly surprised as I do have live plants, change water once a week, vacuum the gravel once a week and rinse out the sponge in the tank water. I think I need more plants! Is there a link to a DIY way to check the nitrate level? < I think the algae bloom is enough of an indicator. It may be high in the water already. In the US in agricultural areas the nitrates are already high from agricultural run off.> I live in a smaller city in China so I may not have access to some type of kit. Thanks again < If you are doing all the other things then I would watch the feeding, remove any excess waste/food after a couple of minutes after feeding. You plants may not be active enough to remove all the nutrients from the water. Maybe even change the light bulbs if you haven't done it in a couple of years.-Chuck>

Nitrate Reduction in Freshwater  8/26/05 Hello, <Hi there>         Once again I have to say: Great site!! Here is my new question. I have been researching ways to reduce nitrate in freshwater aquariums, as I had a problem with high nitrates. I am using a wet/dry filter with bioballs as the media. While doing some research, I came across a product used in Koi ponds called Alfagrog. It is a porous, stable, light weight rock that is used as bio-media in Koi pond filters. I was wondering if this would foster anaerobic bacterial colonies for the reduction of nitrate, in the same way live rock works in the marine environment. Alfagrog rock is sold as SUPRA in the USA. Any thoughts? Thanks, CW <Is possible... best way to find out... to try it. I would arrange this media such that is submerged, underwater. Cheers, Bob Fenner>

Nitrate Problems Hello, I have a 55 gal.. tank with a Tiger Oscar (approx. 6 in.), Pleco (4 in.) and 3 red fin barbs... things have been fine until a couple days ago when I did a water check and the nitrate levels are high.  I just did a 50% water change and added the water conditioner and the levels still are high (nitrate NO3 is 20, and nitrate NO2 is 3.0).  Please tell me what I need to do ASAP so that I can get this under control.   I also noticed that the Oscar looks like he has been scrapping himself up against things (he has marks on his body).  Thank you. < The nitrate is the end of a long chemical process. You need to eliminate the waste that is generating the nitrates. First clean the filter(s). Second is do a 30% water change while vacuuming the gravel. Check your tap water. Sometimes the nitrates are high in tap water from agricultural areas as a by-product from years of over fertilization.-Chuck>

High Nitrates in a FW Tank Thank you for directing me to Dr Tim's website. That and a few other articles I have had time to read has cleared up many of my questions. I look forward to reading more.  I changed 30% of my water and rinsed out the filter cartridges, All stayed the same except Nitrite is now 3.0 instead of 5.0 and Nitrate is still 40 (typo earlier in that I wrote 4 instead of 40). Should there have been more of a change? < Nitrate is the result of long standing waste somewhere in the tank. If the filters have been clean the next area would be in the gravel. This is why we recommend gravel vacuuming so often. Next water change vacuum the crud out of the gravel that has accumulated over time.> I plan to change 30% again in 2 days. I noticed a couple of brown spots on my Anacharis can this be causing any problems? < Anacharis could be the result of shading and could be normal.> Also I forgot to mention I do have duckweed up top, it covers a 1/4th of the surface. < Duckweed is a great indicator of nitrates. If the duckweed doubles very quickly then there is adverse level of nitrates in the tank and the aquarium needs a water change.> Is there a better Ich treatment than what I used? < I prefer Kordon's Rid-Ich.-Chuck> 

Refugium Benefits in Freshwater Nitrate Reduction Morning Crew, <Yawn... good morrow to you> What an informative site! Having come across it a couple of weeks ago, I have been voraciously reading on the many, many topics presented in an effort to become, at least, an informed "aquarist" if not a successful one. <A useful distinction> I've found a lot of material on WWM that discusses the use (and benefit) of planted refugiums for Marine aquariums, however, I am specifically interested in more information on the possible benefits of including them in freshwater (specifically Cichlid) setups.  <Would be similar> I have very much enjoyed keeping approx. 14 African Malawi and 2 Plecos in a 75 Gal, "reef-ready" Oceanic tank for the past year. As background, my aspirations to become an aquarist were not of my own initiative. The tank was donated (dry) to me when a friend moved out of the area. <What a gift!> I inherited the tank/stand, an AMiracle wet/dry, Red Sea protein skimmer and a couple of pumps (tank previously used for SW). Despite the nature of my start, I have done (and continue to do) as much reading as I can to fully enjoy the hobby. Having now become "addicted" to the enjoyment and care of my new pets, I am upgrading to an Oceanic 200g. I know...a "big" jump...but, I love this. I am investing in necessary larger pump (to cycle 8-10 per hour), sump etc. as I expand my enjoyment. I plan to move bio-media, as much water, substrate etc as possible and (once stabilized) fish to the new setup.  My question: I perform 25% water changes every 10 days, regularly rinse mechanical filter sponge on the return, replace the wet/dry Polyfilter pad, etc, and my fish appear healthy (recent Peacock fry) and things are predominantly great. I attempt to feed my friends properly, via isolated float feeder, and on the basis of what they can consume within 3-5 minutes.  Food provision consists of Cichlid flakes, algae disks (2 per day (for the Plecos)), occasional dry shrimp pellets and cucumber slice treat once in awhile (removing what is not consumed in a day). Despite my water changes, I continue to see slightly elevated nitrate levels which I attribute to the food amount, the wet/dry (bioballs) and, of course, the Pleco waste.  <Yes> I use the (probably totally inaccurate) test strips found at my LFS to watch vitals.  <These strips are fine for their (gross results) purposes> Nitrate is constantly borderline between "safe" and "unsafe" (medium pink to dark pink reading). I am wondering if the addition of a well-planted refugium tank (placed beside the sump in the under cabinet) would be of any benefit to overall nitrate control/reduction and water stability in this Cichlid environment? <I do think it will be> As I move to the larger tank, I'll have more room in the base cabinet for such a refugium if there is some benefit to be gained. Also, if a refugium would be of benefit, I would appreciate recommendations as to what types of plants would survive/prosper in the high-PH environment and grow-out to fill the enclosure to maximize the denitrification (is that a word?) <Yes... and I'd look to Anubias (very slow growing) and Crinum... the opposite... two native genera... that enjoy similar water quality as your cichlids> ...effect? <Reduced metabolites, improved water quality... all the ancillary effects, benefits of this> What would be the suggested flow rate to/from the refugium from main tank-volume? <A few... 2,3, up to five turns per hour are ideal> Should this be a trickle or liberal flow (perhaps a % of tank volume per hour through refugium?). Is the use of a refugium a good idea here, or am I going overboard? <Worthwhile> My LFS rep has told me that plants would not survive in this hard, high-PH environment and that the refugium concept for a Cichlid tank won't do any good.  <Mmm, incorrect on both counts...> Obviously, were I to incorporate a refugium, all of the plants would (from what I've read) warrant extra care to ensure continued, adequate oxygenation of the water for the fish. <Not a problem> With circulation rate of 8-10 times per hour and use of air stone bubbler in tank I am hoping that I'd be OK. Any advice, comment you might offer would be very much appreciated. <Better to not have excessive flow here... to by-pass the refugium with some via plumbing...> Many thanks for your collective (crew) support to we ambitious novices!! Best Regards, Brian. <Be chatting, Bob Fenner> 

Re: Refugium benefits in freshwater nitrate reduction Bob, Thank you very much for your informative (and quick) response and time. I know you cover a lot of technical ground for so many, but I do have a follow-on question... final one... for awhile anyway.  Based upon your advice, I will incorporate the refugium with recommended Anubias and Crinum.  If you do have the time to take an additional question on this, here's a little more info on my system/plan:  As I mentioned, the gifted 75G (rr) I've been using with a single Amiracle wet/dry.  In pursuit of my 200g upgrade, I acquired a $$discounted 2nd Amiracle wet/dry (identical to the first) and two T3 Velocity pumps and plan on placing both wet/dries, each with their own pump but connected (via plumbing) in parallel (prevent flooding accident), to support turnover.  I'm hoping the dual T3 setup will achieve 1400-1500gph considering head pressure.  This should give me between 7 and 7.5x H20 turnover of main 200g tank.  Do you think this rate is satisfactory for a 200g with 20-30 (4-5") Africans and 2 Plecos? <Yes... and sounds like a workable plan thus far> Do you think that the waste-producing Plecos (considering the nitrate issue) are of benefit or detriment in a Cichlid environs. would I be better served in finding alternative homes for them? <Mmm, am a bit torn here... on the one hand, some Loricariid species presence may well be of benefit in maintenance, and their waste production is actually minimal... they mainly "re-cycle" other molecular/cellular components... But, if it were me, my tank, I'd rather have Mochokid (Synodontis) species of catfishes... though not algae eaters per se... more "native", tough, accustomed to many African cichlid conditions>   I considered going with a larger, single, higher volume Dolphin or Iwaki pump, but got a fair deal on the two T3s and liked the idea of duality...couldn't get the same deal on two T4's (or 2 of anything else larger) unfortunately. <No worries> Going back to the installation of the refugium, thank you for your suggestions on partial thru-flow.  I forgot to ask what optimal refugium size (volume) would be for this 200g setup...probably as large as I can fit in the cabinet, right? <Yes> I planned on plumbing partial (as you suggest) tank flow output directly into the refugium.  Should refugium out flow be directed back thru the wet/dry (bioballs) or go directly back to pumps/main tank thus bypassing the wet/dry altogether? <Either way... often easiest to have simple overflow to the other transit volume sump> Also, what would you suggest as a substrate for the Anubias/Crinum (regular play sand, Eco-Complete, Mud or other??) <Coarse (one eighth to one quarter) "natural" gravel... to a mix of this and/or marine substrate of your preference... Considering I know not re your source water make-up, you want a material here that will not only suit your plants, but make, keep the water quite hard and alkaline... and be facile in terms of your cichlids' digging potential> ...and should the sandbed be deep to provide anaerobic benefit...primary tank substrate is 2" crushed coral? <Mmm, I discount this here... by and large you want to avoid in situ anaerobiosis in these and most all freshwater systems> How often should refugium substrate be cleaned (or should it)? <Infrequently, in one word... perhaps a stirring, rinsing (with the return pump/s turned off) every few months to a year> Again, thank you so much for your great assistance.  I really appreciate it.  Best Regards, Brian.   <Thank you for your participation, sharing. Bob Fenner>

HIGH NITRATES IN FW I have a 1 year old established African Cichlid tank 75 gallon, 10 small to medium fish. I cleaned tank without fail each month 30% with full vacuum of gravel. Never had test kit or water tested since the beginning. Recently I missed the past 2 months due to business travel. Had the water tested and found the nitrates at 180PPM (yes, 180PPM). I have a canister filter Rena x3 which is cleaned just as frequently as the tank.  I just added a Emperor 400 and performed two 50% water changes with full vacuuming this week about 3 days apart. I am trying to be aggressive to save the fish who have been hanging out at the top (not vertical) and twitching often. These guys are fighters that is why I want to get the Nitrate down. By performing these changes logic would tell me that the levels should at least drop down a bit.  Has anybody ever heard of this extreme condition and when will I see some results from the water changes?   Thanks <You should try and keep the nitrates below 25 ppm to keep your fish healthy. I would check the ammonia and nitrites. They should be zero at all times. With the new Emperor filter this should not be a problem once the bio wheels are seasoned. Check your tap water for nitrates. In some agricultural areas the ground water has a nitrate level as high as 50 ppm from the tap. Assuming the nitrate levels of the tap water are low and the filtration is working properly you may need to perform your maintenance procedures more often. Start out by servicing the filters and doing a 30% water change once a week. The canister filter can be a real pain to change but all the waste that accumulates their is not gone out of the system. It is just contained and adding to the nitrate problem until you decide to get rid of it. Cleaning it once a month is too long. Feed only enough food so that all of it is gone in 2 minutes once a day. Use a vegetable based food for Lake Malawi cichlids. You might try Amquel plus . It is supposed to reduce nitrates. -Chuck> 

Denitrators, FW I have a small 25 (I think) gallon tank with plants and 10 very small fish and I'm interested in buying a denitrator. Firstly, do they work? Secondly, is it too much for a small tank such as mine? BTW it's a freshwater tank. Thanks for your input. -Jessica Wertz <There are purposeful denitrator "filters" sold for freshwater systems... some do work moderately well (better than marine ones for sure), but I'd like to ask, what sort of concentrations of nitrates are you experiencing such that you're interested in such an addition? And to state that you can very likely get sufficient anaerobic denitrifying action through the addition of a ceramic or fused-glass bead media... to an outside hang-on or canister filter... Bob Fenner>

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