NO3 FW Sources F

FAQs on Marine Freshwater Quality involving Nitrates: Sources

Mmm, mainly too much livestock, over-feeding, under-filtration, poor maintenance practices (lack of water changes esp.), but tapwater can be a sizeable source, as well as some types of decor and "water treatments", and from driving nitrification (aerating large amounts of wet-dry media)

High nitrate levels 11/12/14
Hello! I have a Fluval 206 canister filter in my 30 gallon guppy tank. I just put the filter in less than a month ago but I'm getting nitrate levels at around 40. Could it be the filter causing this?
<Mmm; yes; depending on the filter media employed and the make up of the rest of the system>
Im using Clearmax in it which is suppose to help but hasn't.
<Mmm again>
I'm not over feeding my fishies so I'm otherwise clueless. Thanks for your help!
<I'd just do more regular (like twice weekly) 25% water changes for now... and see if the NO3 trends down.
Bob Fenner>

High Nitrates after use of Melafix -- 03/20/08 Hello, <Hi there> First, let me say thank you for your wonderful site, which I return to every chance I get. You have been kind enough in the past to help me; and I am hoping for your assistance again. <Will try...> I have a 36 gallon freshwater tank, lightly stocked with 10 fish. When my tank was new (15 months ago) it always had an alkaline PH of about 7.2. <... Mmm, not "that" alkaline... In fact, some good reasons to have a slightly elevated pH... NealeM has a nice article re: http://wetwebmedia.com/FWSubWebIndex/fwhardness.htm and the linked files above> As my tank matured, I was told that it would probably become more acidic, which it did. It has been around 6.6 for the past few months now. However, 2 weeks ago, my Boesemanni Rainbowfish got injured in a castle ornament (which I have since removed) incurring significant scale damage. I added Melafix <...> to the tank because I had heard great things about it speeding up healing. Well, it worked. He was completely healed within a week. <Might've taken seven days (or less) w/o...> I was performing modest 10% water changes every other day for the length of the 7-day treatment in an attempt to keep the water pristine. During the course of the treatment I only tested for ammonia and nitrite to ensure that my bio filter was not being affected. Ammonia and Nitrite always tested at zero and continue to do so to date. After treatment ended, I put carbon in the filter (Eheim canister) and performed a 25% water change. I tested my water parameters a few hours later and was very surprised to find high nitrate levels of at least 40ppm, but could possibly have been higher. It is very hard to differentiate on my test kit at any level higher than 20ppm since the shades of red are almost identical. <Mmm, often diluting samples by half (by adding "clean" water of the same approximate volume...) can/will bring readings back "on scale"> My nitrates never exceeded 20ppm before this, as I religiously perform 25% water changes every two weeks with a complete gravel vacuuming. I theorized that the Melafix must have been responsible since it is a plant derivative and probably contributed to the dissolved organics in the water. Could this be the reason? Also, as I feared, my PH level has dropped to the lowest range on my test kit (6.0-6.3). <All are possible interactions, yes> I have been doing daily 15% water changes since this occurred and the nitrates seem to be dropping (hard to tell once in the "red" range on the test kit) and my PH did go up temporarily last evening to 6.4, but had dropped again by this morning. I don't wish to stress my fish, who all appear fine at the moment, so I hesitate to do large water changes for fear of the PH rising too quickly. <You are wise here> Should I proceed with the daily 15% water changes, or do you feel that this is insufficient to correct this issue in a more timely manner. Is there anything I could have missed (besides the obvious of not using Melafix in my display tank anymore). I thank you in advance for your assistance. Michele <Mmm, I think you're doing fine. I am NOT a fan of the "fix" products by API, but there are folks here (WWM) who are a bit more charitable. Am a bigger promoter of the use of real medicines. Bob Fenner>

Follow-up on High Nitrates/low PH after Melafix use Hello again, <Michele> I wrote to WWM earlier in the week regarding experiencing high nitrates and subsequent low PH in my tank after using Melafix to treat a injured fish. For your reference, I have included my original correspondence which Bob Fenner answered and was kind enough to assist me with. I have been doing daily modest water changes to bring down the nitrate levels, which has vastly improved (currently reading in the 20ppm range) but of course I'm still working on getting it even lower. However, in tandem with the high nitrates, my PH level dropped from 6.6 to the lowest range on my test kit (6.0-6.3). Water changes have resulted in the PH rising to 6.4, but this effect has been temporary, usually dropping back down within 24 hours. I realize that larger water changes would yield quicker nitrate reduction, but I don't want to stress the fish in case the PH does increase too rapidly so I'm proceeding cautiously. <You are wise here> But despite the nitrates being reduced, the PH is not climbing back up as of yet and stabilizing as I had hoped. I was somewhat puzzled about this, so I went to your site and researched some possibilities as to why. In doing so, I realized that I did not know what the KH or GH of my source water was, so I purchased a KH/GH test kit to find out. <Ahh!> I live in New York, and we have very soft water, which has almost no KH/GH, which I confirmed with the test (only 1 drop yielded a slight tinge of color). I know now that this is not ideal, and that PH drops can occur without enough buffering; <Yes> however I am very leery of adding any chemicals to the tank for fear of rapid and/or wide PH fluctuations which can be much worse than a stable but low PH. <Best to make all such changes gradually, through/by way of the change out water... modify it and add it to the system> My father has been using the same source water for 30 years, and has successfully kept tropical fish without the use of any chemicals to alter PH or hardness. His philosophy is to keep fish that will adapt to your conditions and thinks I am overly concerned about this. <A valid concern; particularly if only keeping livestock that "enjoys" softer/acidic water...> I tend to agree with his philosophy but my real concern is the low PH hindering the nitrifying bacteria. <Also a valid concern> I have read that at lower PH levels, the bio filter does not work as efficiently. <This is so> Is this true, or does PH have to much more acidic for this to occur? <Slightly alkaline is better... the forward reactions/nitrification are reductive in nature... drive pH down... so having some biomineral in place...> If I continue with the daily water changes and get the nitrates down to about 5-10ppm and keep them there with a more frequent maintenance regimen (perhaps a weekly water change instead of bi-weekly), will the PH increase to where it was a few weeks ago, or without sufficient KH will it remain low no matter how many water changes I do? <If there is no addition of alkaline material (esp. carbonate, bicarbonate) from somewhere, the GH, KH will not change... If reductive processes continue, the pH will drop...> Forgive me if this has been explained somewhere on your site. <An, no worries> Be assured that I have been reading, but I find this issue of hardness somewhat confusing and wanted to check with someone from the crew before deciding on a course of action. Also, please note that prior to adding the Melafix a few weeks ago, I did not have excess nitrates nor any problems with a sudden PH drop so I am hoping that just keeping the nitrate level extremely low will get my tank back to where it was a few weeks ago. I had also read Neale's suggestions to some people about using crushed coral in the filter to raise KH, but I don't want my PH to rise by very much. <Depending on how much, how soluble, this addition is very safe... will not raise pH much, very quickly at all> Since my source water is on the acidic side (6.6-6.8), my goal is to get the tank PH as close as possible to my source water. Is it possible to use the coral and only increase the KH and PH slightly rather than to the basic side of the PH scale? <Yes... could be placed in a filter, bag... in a container with your make-up water... allowed to "soak" for a few days...> I'm somewhat confused because I have been hearing/reading conflicting information about their use. How do you suggest I achieve my goal of increasing my PH to about 6.6 - 6.8 and stabilizing it? <Mmm, the water changes you're doing... with the addition of a bit of sodium bicarbonate (very safe) or a modicum of commercial aquarium pH buffering product> Once again, your advice is greatly appreciated and invaluable. Michele <Let's keep chatting this over till you feel comfortable with your understanding of the underlying principle/s here... This aspect of water quality (pH, alkalinity/acidity... "hardness") is too wordy in English unfortunately... But once you grasp it... Cheers, BobF>

Re: Follow-up on Discovery of Low KH after High Nitrates/low PH w/Melafix use 3/26/08 Hello Mr. Fenner, <Just Bob please Michele> Thank you so much for all of your assistance in explaining how KH factors into maintaining PH. I have been doing some more reading and if I am understanding correctly, the baking soda method needs to be replenished with each water change (outside of the system in the new water) . <Yes, this is best> Since I'm not great at chemistry, and thus would be experimenting with the amount to use to reach my goal, I fear that this leaves a lot of room for human error. <Actually, not much error possible. This practice, with Baking Soda is quite safe> So I think I feel more comfortable with a slow soluble carbonate substance such as crushed coral or even crushed oyster shells and will experiment with a small amount in the filter as a first corrective step to increase KH. The only crushed coral I have been able to find however has aragonite mixed in as well. If I understand correctly, this makes it more soluble, so is this still acceptable for my purposes or would this make the tank too alkaline? <No, not likely> If not recommended for my purposes, I have also been able to locate crushed oyster shells packaged as a "bird feed". <Ahh! This material... usually some type of Dolomite ("Tapa Shell)... a compound of calcium and magnesium carbonates CAN be very soluble... and a mess to handle/deal with... too "cloudy" in preparation/use> In the meanwhile I will continue with my water changes to further decrease the nitrates and proceed from there. Thanks for the offer/opportunity to continue chatting until I get a better grasp of the subject matter. I'm honored that you would take additional time from your busy schedule to assist me. Michele <Am out in Malaysia currently... where am dreading the Net slow-down. Cheers! BobF>

Re: Follow-up on Discovery of Low KH after High Nitrates/low PH w/Melafix use 3/30/08 Good evening Bob, <Mich> I hope your trip to Malaysia is going well. <Yes... but the Net is slow... and intermittent> I did purchase the crushed coral and added a very small amount to the filter on Tuesday. I figured I could always add more if needed. Since my nitrates are now in 10ppm range, I've stopped the daily water changes and will continue as necessary to keep them low. The PH was holding steady at 6.4 for a couple of days without dropping. Today it has increased to 6.6, so it seems that the coral is working. My KH test kit still is reading very low (1 degree), but I'll give it some more time since I seem to be making some progress. And speaking of progress, I actually managed to talk my father into adding some coral to his filter as well. <Ahh!> I referred him to your site and our discussions; and I guess he realized that no matter how long you've been in this hobby, there's always something to learn. <Is so for me... and I am indeed an old timer in the trade, science and hobby> Thanks again for your help. I have been enjoying chatting with you. I will keep you posted on the progress of my tank, but I'm confident that the coral will serve the purpose. Michele <Bob Fenner>

High nitrates, FW 2/5/08 Hi, <Hail and well met.> My nitrates are undergoing a spike. After numerous water changes and no change, I decided to check the well water. Seems with the freeze and thaws we are undergoing the well has been contaminated. The water both out of the well and in the tank (API liquid test kits) is about 40mg/l. This normally would be a reading that would indicate the need for an immediate water change, but of course not under the circumstances. <Nah... 40 mg/l is well within the toleration zone for most freshwater community fish, particularly if they're acclimated to it. Nitrate is (under lab conditions) known to be something like 1000 times less toxic than nitrite. While dumping a fish from low nitrate water into high nitrate water is harmful, if they experience gradual changes, they seem to adapt well. There are exceptions though, primarily Mollies and most of the Cichlids, which react badly to nitrate once it gets above a certain point. That said, the nitrate level in London, for example, is about 50 mg/l right out the tap, and lots of Londoners keep fish without problems! This isn't an excuse for skipping water changes of course, since water changes are about a lot more than nitrate. Provided you're doing 25-50% water changes per week, I wouldn't be overly concerned about this moderately high level of nitrate.> If have been reading up on solutions for high nitrates, but most involve changing my water chemistry (RO method which is relatively expensive, never mind the plumber) My well water is hard and the tanks have been stocked accordingly. I was buying plants at a rather slow rate and yesterday bought a large number to at least try and help with a biological control method and reduce the naturally occurring one of algae growth. From my reading here today, I suspect that will not be enough. <Plants can help, but you do extremely fast growing species under intense lighting.> It seems the only causalities so far are a couple of zebra Danios and as I recall from my reading here yesterday (in a effort to figure out what was wrong with them) they are particularly sensitive to high nitrates. <Not heard of Danio spp. being nitrate sensitive. They don't like "old" water certainly, but not sure if that's nitrate-specific or more about water quality generally. In any case, people can and do keep Danios in water with quite high levels of nitrate in cities without problems.> Other species include swordtails, platys, Boesemanni and dwarf blue Rainbowfish (have read that these too can be very sensitive to nitrates) Plecos, Corys, diamond tetras.....though so far they are demonstrating no signs of stress. <Wouldn't expect them to.> The information contained on this site seems to indicate that additives and/or filters designed for nitrate removal have negligible effect. Is my only option to dilute the well water with bottled water? <Wouldn't bother. Nitrate-removal systems in marine aquaria make sense because the baseline is very low (ideally 0 mg/l) and the level of stocking is low as well (so the rate of nitrate accumulation is low). In your freshwater tank these factors aren't the same, and you'd need a huge nitrate-removal system to reduce 40 mg/l down to 0 mg/l quickly enough to make any difference.> This would indeed not be easy are we are talking about 110 g tank as well as some smaller ones. And of course, I do not live in town. However, if you think that this in the only option, I guess I shall start toting..... <I'd do this: sit back and watch what happens. Keep up with your normal water change routine, using the well water. I'm not a great fan of doing massive amounts of work to water chemistry if it can possibly be avoided; the ideal is to keep fish that like your local water. If it's hard and alkaline and has 40 mg/l nitrate, then that's the situation and you can choose fish accordingly. I will make the point that rainwater is what I use to dilute the water I have to work with, which I mix 50/50 with tapwater to get something moderately hard and neutral in pH and with half the nitrate amount. Collecting rainwater is easy to set up and costs nothing to do, but of course it does depend on your local climate. Here in England, rain is rarely lacking! If you live in Arizona, this mightn't be an option.> Thanks in advance for your assistance....again Cheers Aileen <Cheers, Neale.>

Re: high nitrates, FW 2-05-08 Thanks Neale, <Hi Aileen,> I guess I was so used to having low nitrates and read often in the pages of this web site the preference for maintaining low to nil nitrates. <Ah, don't get me wrong: low nitrates are a good thing. But when it comes to standard community fish -- guppies, Danios, Corydoras, etc. -- nitrate levels as high as 50 mg/l are not likely to cause problems. Mollies and dwarf cichlids are the notable exceptions. So you should certainly aim for low nitrates, but if you can't get a nitrate level of zero, don't lose sleep over it; your fish won't be all that bothered.> Then to make matters worse just after discovering the change in the well water, I had two Danios under obvious duress with no other symptoms. One had died, the other seems to be recovering in quarantine with no meds. Just salt and a little peace and quiet. <Good.> Just in case, I did test the other parameters and they are fine at 0. I shall try to ignore this twist on the continuing saga of ever changing well water..... <Indeed.> By the way, I do not know how much you may recall about my previous emails you answer so many, but I gave up on obtaining more swordtails for now. That said, my remaining female has given me a whole school of them. They are two weeks old now and growing like weeds. Spoiled though, they have bottled water mixed in! <DO remember Swordtails, like most livebearers, like their water as hard as possible. Hardness is your friend with livebearers.> And I am in Ontario, lately it seems I could be collecting rain water one day and buckets of snow the next! <Well that's good then, no? Collecting rainwater is actually kind of fun, because you start glowing with pride afterwards for doing your bit to save the planet AND you get to keep funky soft water fish from the Amazon or wherever.> Thanks again Aileen <Cheers, Neale.>

Excess nitrates problem, FW 11/1/07 Dear WWM, <Melissa,> I have/had a 5 gallon tank with two panda Corys, mechanical and biological filtration. <Hmm... 5 gallons too small for such fish, and really too small for any fish. The main problem is a lack of stability, so even if a 5 gallon tank is fine one day, by the next it can be a death zone. The bigger the tank, the slower such changes, and the more time you have to fix them. Experienced fishkeepers can usually run a 10 gallon tank safely enough, but for beginners there is no doubt in my mind a 20 gallon is the bare minimum for anything like a consistent chance of success.> Yesterday when I left my house, my fish were fine. One of my Corys was displaying some clouded eye a few days ago, but it seemed to be improving. The other Cory was unaffected. <Cloudy eyes don't tend to go away, and even if they do, they're really an indication of infectious agents in the water. In other words, this should be an alarm bell.> When I got home about seven hours later, there were these tiny worms in my tank. They are very small, ranging from about 2 to 10 mm long, almost translucent, and free-swimming. They resemble Planaria but are not white. I suspect them to be nematodes. <Quite possible. Nematodes such as these are harmless, and simply turn excess food you are giving your fish into more nematodes. Cut back the food, clean the tank more rigourously, and the nematode population will die back. Again, an alarm bell.> I have not added anything new to my tank recently. My java fern has also started yellowing suddenly for some reason, I don't know if this has anything to do with it. <Likely not; are you fertilising the water? Like any plant, Java fern relies on minerals such as iron and magnesium from the water. This is used up over time, so at least monthly you need to top up with plant fertiliser.> Plus, there are tiny white specks crawling on the inside of my tank walls. <Could be nematodes, planarians or even some sort of tiny crustacean such as Ostracods.> I also lost both Corys over the last 12 hours. <Sorry.> I suspect both the worms and the fish loss to be due to excess buildup of nitrates in my water. <Wrong. The nematodes and the nitrate levels (which you don't quite) are a product of poor aquarium care. Provided you don't give fish too much food, there should be no food for nematodes to turn into even more nematodes. Likewise, nitrate comes from food, not thin air. So if you have relatively high levels of nitrate compared with the water you put into the tank, this means you are adding too much food and/or not doing enough water changes. Bottom line, the nitrates and the nematodes were warnings about a systemic problem with the tank; without fixing that problem, you allowed the situation to become critical, resulting in dead fish.> However, I don't see how this could happen as I siphon thoroughly once a week along with 20-25% water changes. <Not enough. The smaller the tank, the more the water changes need to be. Minimum, 50% a week for this system.> I also underfeed. <Apparently not, or there wouldn't be any worms. Understand this: nematodes are animals. They eat stuff. They eat fish food. They can't survive on just water and gravel. So if the nematodes are multiplying, that can only mean there is "stuff" in there for them to eat and turn into baby nematodes.> Although I did a full siphon and water change two days ago, yesterday I was still able to siphon out a very large amount of dirt from my gravel. This included white and brown specks about 1 mm as well as microscopic specks that looked more like dust than anything. <Organic detritus. This is the stuff you need to remove with each water changes. In a bigger tank, this really isn't a problem, but in a small tank, organic decay can be critical, resulting in things like rapid pH drops.> Today, I siphoned again, and even though I siphoned yesterday and did a 40% water change, today after an hour of siphoning I was still able to stir up a significant amount of this dirt. <Bizarre. Let's review how the gravel should work. In a tank with an undergravel filter, you need around 5-8 cm of gravel, through which water is drawn. Each week you need to stir the gravel and siphon up the solid waste that accumulates there. In tanks without undergravel filters, you don't need a deep bed of gravel unless you have rooted plants. In your case, if the only plants you have are Java fern (which you NEVER stick in the gravel but attach to wood/rock) the gravel need only be 0.5-1 cm think. Enough to cover the glass but no more. This should be very easy to keep clean. In tanks with plants that have roots (Vallisneria, Amazon swords, etc.) the substrate needs to be much deeper, around 10 cm. Actively growing plants will largely keep the gravel clean by themselves, and to a degree use the organic wastes as a source of nutrients.> I am not sure what is causing this huge accumulation of waste in my gravel. No amount of siphoning seems to decrease this amount. <Put the filter in a bucket of aquarium water and leave it running, and then take apart the tank and give it a thorough clean. Return only so much gravel as you need to cover the glass.> Ammonia and nitrites are both at 0. What should I do? <Clean the tank, and review the basics of setting up and maintaining an aquarium. Once you're happy you have them covered, go get some more fish, but choose something more suitable for a 5 gallon tank, such as a Betta or perhaps a few shrimps and small gobies.> -Melissa <Cheers, Neale>

Re: Excess nitrates problem 11/1/07 Hi again, <Greetings!> I understand that 5 gallons is difficult to keep balanced. I'm preparing a 15 gallon now...don't have room for anything bigger. <Good. While 15 gallons is still on the small size, it's certainly much easier to maintain than a 5 gallon tank.> My java fern is rooted to a piece of wood. I also have a piece of driftwood on which I am keeping java moss. <Correct maintenance for both these plants. If placed in the substrate, they rot.> My gravel is about 3/4 of an inch deep. <Use less. In a tank without plants or an undergravel filter, you really only need enough to cover the glass. I prefer to use sand with Corydoras than gravel; you will immediately see changes in their behaviour as these catfish happily root about in a more natural way. Aquarium sand can be used, but non-calcareous smooth silver sand (silica sand) costs next to nothing and can be bought at any garden centre.> I will take the tank apart and clean it as suggested. Should I empty out all the water as well when I do this? <Yes. Of course, make sure the new water is dechlorinated and at roughly the right temperature for your fish, i.e., not too cold and not too hot. Corydoras panda (which I think you said you had) like water on the cool side: aim for 20-25C, but no higher and not substantially lower. Do keep the filter running in a bucket of aquarium water while you're cleaning the tank; otherwise, the bacteria will start dying, which is a Bad Thing.> Thanks for the help. -Melissa <Good luck, Neale>

Bad link on your site... and FW algae, nitrification issue 10/15/07 Hello Crew member, FYI, you have a nasty link on your site located at /diatomfltfaqs.htm. It is the 9th post from the top, titled ?Re: Diatom Filtration? and the link is <http://www/> http://www dot aquarium advice dot com/viewtopic dot php?t=3250. (link is retyped so to prevent you from accidentally clicking it) The link attempted to install the following 3 viruses: Exploit-MS06-014 (Virus), Exploit-CVE2006-3730 (Virus), and VBS/Psyme (Virus) in rapid succession. My virus software stopped the attack, but my system was frozen for several minutes. <Yikes... I see what you mean... Have removed this link. Thank you> While I am taking the time to write you, I might as well ask a question. I have spent many hours reading your site and have asked a few questions in the past as well, and I must say that you people are the bomb. <La bomba!> Currently, I have a green water situation that seems to go against standard logic. In a nut shell, the problem worsens each time I vacuum the gravel or clean the filter. Several months ago the problem was not green water, but rather cloudy water. If I left the tank to its own (if I neglected it), it would clear up, but nitrates would rise as well to the point that water changes would have little impact. <Mmm, you need/want more "filtration"... low/ hypoxic to no/ anoxic spaces...> It is then that I clean the filter and/or the gravel to slow down the production of and lower nitrates, but that causes the water to turn cloudy. I try to keep the nitrates below 10ppm, but when water changes will no longer keep the level below 20ppm is when I know I need to clean the filter and gravel. <Yes... a common situation> After purchasing 2 Plecos who do a wonderful job of cleaning the glass, gravel and dÃ©cor of all visible algae, the problem of cloudy water became a problem of green water, and boy is the water green. Visibility in the tank is about 4 inches, and it has been that way for about 2 weeks now. I am at a loss. All water tests are currently and stay great with the exception of phosphates, which I have not tested because I use to use a phosphate buffer to control Ph so I knew the reading would be high. I have since quit using the Ph buffer and have let the Ph rise as a result. High or otherwise, phosphate levels have no impact on the cloudy/green water. I have read so many of your articles and FAQs that I feel like an expert on the subject, but something is amiss. More info; I can't keep plants because my silver dollars will eat them. My tank is 75 gallons. I have 4 silver dollars, 3 Corys, 2 bushy-nosed Plecos, and 1 blue ram. I wonder if I do not have enough fish to support the biology in the filter? Is that possible? When I had many more fish I didn't have this problem. I have an EHEIM Pro 2 canister filter running about 275GPH and it is full of bio balls that I am very careful to not tamper with. <Good> The tank has been running for about 3 years. I use RO water treated with RO right (2dGH) and baking soda (3dKH). Everything in the tank is plastic, or epoxy coated except 3 pieces of Malaysian drift wood. <This, these should help> No nitrites, no ammonia, Ph 7.6, (I prefer lower but cannot seem to keep it down without using phosphates), nitrates 5ppm at last check. I need to get to the root of the green water. I have had aquariums for over 30 years, but never has issues like this. I am trying to keep this short, so will cut it off here. If you need more info please let me know. Best Regards, Scott <Not to make too much of a simple/simplified response sans explanation, but the "answer" to the situation here is more fine substrate... like another inch or so of gravel... or the addition of ceramic ring, sintered glass media... for the bioballs. This will shift more of nitrogen cycling to/back to denitrification... Bob Fenner>

High Nitrates in a Young Tank, UGF - 05/13/2006 Hi Crew. <Hi.> Thanks so much for such an interesting and informative website! I have spent countless hours reading the many fine articles and FAQs all of you provide. <And thank you for these kind words! I'm glad the site is of use to you.> Now I have a question I can't find a specific answer to. Hope you can help me. I have a 75 gal. freshwater aquarium that has been running about 14 weeks. It has gone through its cycle and has a medium bio load. <Medium being....?> I do regular water changes; 15% every 2 to 3 weeks. Filtration is Emperor 400 with bio wheels... UGF with 2 -145 gph powerheads. (I know, I know, everyone hates UGF's but me!) <Mm, they can be useful, but tend to trap detritus that ends up "stuck" down there, and gives you nitrate, even pH, issues....> I can not keep my nitrates down. <There ya have it.> Do I have too much bio filtration? <Not necessarily. Tough to say without knowing what's in the tank. A "medium" bioload to you may be "severely overstocked" to me.> Should I remove the bio wheels from the 400? <I wouldn't. The BioWheels, though a good spot for bacteria to live, can't compare with the amount of bacteria that live in the substrate of a tank. I would like you to consider running the UGF in "reverse" so detritus can't be trapped beneath the plates if you are very keen to keep using it. If the nitrate trap of the UGF is not at fault here, then you'll likely need to either decrease your bioload or increase the amount and/or frequency of water changes.> Thanks so much for your time... DR <Wishing you well, -Sabrina>

High nitrates after 4 months! - 5/2/2006 <Hi, Christine. Tom with you.>> I've had my 30 gallon tank set up for 4 months. I did the fishless cycle and all the levels were great! <<Kudos to you and more kudos!>> I added fish and it all came undone. <<Eeek! What happened?>> 6 African Cichlids <Cichlids>> live in the tank with a coral substrate, plastic plants and a 300 GPM waterfall filter. <<Uh, oh. Too many of this species for a 30-gallon tank.>> The nitrates are over 40 ppm no matter what I do or how often I do it. Fish are very healthy....growing like bad weeds and everyone gets along as much as cichlids are able to get along. <<Did you research these fish, Christine? (More to follow...)>> I've tried adding carbon to the filter media, <<Won't do it...>> weekly 40% H2O changes, vacuuming more often. <<Very good practice. Hoping you're vacuuming deeply (all the way to the bottom) and not just "superficially".>> What have I missed? <<You have too many of these fish in the size tank that you have. Your filtration is likely undersized for the situation. You don't mention how much you feed, or what you feed them but, they can be "messy". Uneaten food/detritus will contribute to nitrate levels.>> Does it really matter anymore if they are healthy that the nitrates are high. <<You REALLY need to research your fish, Christine. High nitrate levels can lead to HITH/HLLE disease in Cichlids. Your "target" should be less than 20 ppm. With Cichlids, I would aim for < 5 ppm to be on the safe side. (Side note: Unless you have Dwarfs (and they aren't if they're African, i.e. Malawi, Tanganyika, Victoria), you'll need a larger tank in the future.)>> The other chemical levels are well within normal parameters; ammonia is nonexistent, no nitrites and I have hard water. <<All here is very good, Christine.>> Thank you in advance for your help Christine <<You're welcome. Tom>>

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 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>

Nitrifying Bacteria Doing Their Job 12/24/05 I was wondering if you could help me. I have a fresh water tank with under 10 mid size fish. I am pumping the water fairly fast into a (vertical) plastic bottle with holes cut in it filled with bio balls and some white filter cotton material. the water also goes through a mechanical filter (sponge) first, and I replace about 20% of the water once a week and clean a quarter of the balls once every 2 weeks. However, algae is growing like crazy in my tank...there is not too much light either. Do you think this is because my bio balls have become a nitrate factory? <Check the nitrates. I am sure they will be high. Filters catch the waste and break it down from toxic ammonia and nitrites down to less harmful nitrates. They do not remove the nitrates. These must be removed or diluted with water changes or by using live plants. You can get ahead of the game by cleaning the filter often, vacuuming the gravel while doing a water change, and by feeding your fish once a day. Fed them only enough food so that all of it is gone in two minutes. Ring out the sponge too. This should help.-Chuck>

High Nitrates, And How To Reduce 'Em - 09/21/2005 I continue to have HIGH nitrate levels....but my Cichlids are reproducing.... WHAT CAN I DO to make it better for them????? I know there is something to make the nitrate levels go down....but WHAT IS IT????? <Simply water changes; nothing more. Find the reason for your high nitrate (undergravel filter plates, unclean canister filter, unvacuumed substrate, overstocked tank, poor husbandry....) and fix it. Wishing you well, -Sabrina>

Freshwater Nitrate Questions 8/6/05 Hello, <Hi there> Your site has provided me with sound advice in the past. Here is my present question. I've had my new 125 gal planted community tank up for about 5 weeks. This was an upgrade from a 55 g. When I did the upgrade I moved everything (water, plants, rock, wood, fish) into the new tank to reduce cycling. My filtration consists of a large wet/dry filter that is new and 2 Penguin 330 bio wheel power filters that are completely seasoned from the old tank. My water parameters have me puzzled. Ammonia and Nitrite 0, PH 7.2, Nitrates above 100ppm. <... from the wet-dry...> I have been doing 15 gallon water changes every other day for 2 weeks and this week I did 2 30-40% water changes with thorough gravel vacuuming. There was quite a bit of dirt that came up with the vacuuming. I think a lot of the dirt is from the old gravel. My substrate consists of all the old gravel from my old tank plus 50lbs of new Fluorite and 50lbs of new 2-6 mm pea gravel. I use Amquel plus for my water conditioning, which is supposed to reduce Nitrate. I am wondering if the Amquel locks up the Nitrate, and my test kit is still reading it. Or does the Amquel neutralize it? and how? <Does not> My nitrate readings have not changed. My tap water has no Nitrates. I clean all the filter sponges (power filters, pre-filter, and drip plate) once a week to remove the accumulated organics. I have mainly Java ferns for plants and they seem to be doing great. I ordered more plants and am hoping this will lower my nitrates. <May, in time> I don't think my fish load is causing the problems. I have 3 3-4inch Boesemanni Rainbows, 3 4 inch Clown Loaches, 1 6inch Royal Pleco, 1 12 year old 5 inch Chinese Algae Eater (very docile), 1 4 inch spotted Raphael cat, and a couple of Corys. I suspect my feeding to be a little excessive, so I am going to switch to every other day feeding. What is your opinion about flake vs. frozen brine cubes? <Neither are good exclusively> The flake food seems to disintegrate into tiny pieces when the fish eat it. Would using frozen brine exclusively cut down on food pollution? <Umm, no> I am looking for a way to reduce my Nitrates, because I seem to be unsuccessful. Thanks, CW <Please read here: http://www.wetwebmedia.com/wetdryfaqs.htm and the linked files above. As you will see, the technology of wet-dry filtration often "overdrives" the forward reactions of nitrification... there are a few countervailing strategies... Bob Fenner>

Wet/Dry and Nitrates in Freshwater - 08/19/2005 Hello, <Hi.> Thanks again for the great wealth of information. I have been doing a lot of research on wet/dry filters. There seems to be a lot of info on using live rock instead of bio-balls in reef applications for the reduction of nitrates. Are there any options for freshwater systems that use wet/dry filters? <As in, similar to live rock and opposed to bio-balls?> What about the use of sintered glass in the bottom of the sump under the bio-balls? I am looking for a way to control nitrates without ditching my wet/dry. <Can you plant this tank? Vascular plants will soak up that nitrate.... Look to floating plants like water lettuce, water hyacinth, and even <yuck> duckweed if you can do so, otherwise a great deal of fast-growing stem plants (Anacharis/elodea/Egeria, for example) will help....> My nitrates were well over 100ppm a couple of week ago, but after a lot of water changes, it is down to an acceptable level of 20-40 ppm. <Wow, still high!> Any thoughts? <How much bioload is in this system? It is rare for a properly stocked freshwater tank to build up nitrates that high, wet-dry or no.... If the tank is properly stocked, is there perhaps an undergravel filter plate in place (still in use or old)? Is the substrate/gravel very deep and not well/often cleaned? Perhaps a canister filter on this system that has not been cleaned in a long, long time? Look for the causes of this problem (not likely the wet-dry alone) before trying to solve....> Thanks, CW <Wishing you well, -Sabrina>

Re: Freshwater Wet/Dry and Nitrates 8/19/05 Hello, <Hi there> Thanks again for the great wealth of information. I have been doing a lot of research on wet/dry filters. There seems to be a lot of info on using live rock instead of bio-balls in reef applications for the reduction of nitrates. Are there any options for freshwater systems that use wet/dry filters? <Sure> What about the use of sintered glass in the bottom of the sump under the bio-balls? <Yes> I am looking for a way to control nitrates without ditching my wet/dry. My nitrates were well over 100ppm a couple of week ago, but after a lot of water changes, it is down to an acceptable level of 20-40 ppm. Any thoughts? Thanks, CW <How about a DSB? Live plants? Bob Fenner>

Wet/Dry and Nitrates in Freshwater - III - 08/19/2005 Thanks for the reply. My aquarium is a 125 gal that has been running for about 6 weeks. This is an upgrade from a 29 and 55 that I combined into the 125. When I did the upgrade, I moved everything from the old tanks into the new. I suspect a lot of the nitrates are coming from the substrate. When I did the upgrade, I moved all the gravel from the old 55 into the new tank and added 50 lbs of Fluorite and another 50 lbs of new gravel. The old gravel was pretty dirty, but I wanted to preserve the bacteria, so I did not rinse it. <This could be the issue. I would try doing a pretty deep gravel vacuuming....> My fish load is pretty light. 3 4-5in clown loaches, 3 4in boesemanni rainbows, 1 6in royal Pleco, 1 5in Chinese algae eater, 1 4in Raphael cat, and a couple of Corys. <Yeah, that's not the issue, then.> My wet/dry is moving 980gph. I am also running 2 seasoned penguin 330 bio-wheel power filters from the old tanks. All my water parameters are good--except for the nitrates! My plant load consists mainly of Java Ferns that are doing great. I recently added some floating Watersprite that is growing well. <Ahh, these will suck up nitrates so well, they won't know what hit 'em! More of these, and other such plants will do a great job.> My light is 2 55w compact fluorescents in a 4 foot fixture. The light is centered over the tanks, so I have some subdued lighting on either end. My loaches and Corys seem to appreciate that! I've tried some stem plants, but my Royal Pleco eats them. <Try Anacharis/elodea/Egeria, either loosely anchored, or floating.... Though he'll nibble it, it should be able to grow quickly enough to compensate. Vallisneria may also be of use, here, and the large Crinum thaianum.> I have been making steady progress in the reductions of nitrates with water changes. When I first tested the nitrates they were off the chart--deep red on the test kit. Now, 5 weeks later, I am around 20-40 ppm, according to my tests. <A significant change, indeed.> Thanks, CW <Wishing you well, -Sabrina>

Effect of Medication on Nitrates 7/22/05 Could you please tell me if medication (Jungle Brand- Parasite Clear and Fungal Clear) added to a freshwater tank would increase the nitrates? <Mmm, don't think so... at least not directly... the principal ingredient in these products is "salt"... which, if anything would subtend the metabolism of all microbes... including nitrifiers. Bob Fenner>

URGENT * high nitrates, need immediate assistance... much more trouble than this 07/02/05 Hi there, novice here, I've been reading up a lot on your website and I am very pleased with the quality and quantity of information, thank you. So, here's the scoop: EQUIPMENT: 1 55 gal. tank (fresh water), 1 75 gal, limit bio wheel penguin filter, 1, in tank, tube heater (approx. 12in. long and 3/4in. diameter but plenty large for the tank), and 1 double hose air pump (air rocks located on both ends of the tank). LIVESTOCK: 1 spotted eye Oscar 6'', 1 silver Arowana 9'', 1 fire eel 15'', 2 blood parrots 3-4'' (one developing black spots within the last two weeks, the other's scales seem to be blemished [best described as one's hair when he wakes in the morning, but only in one spot as opposed to all over, approx. 1/8'' diameter on one side] and not discolored, 1 Large South American Cichlid (heard he's named after a famous boxer??) <Maybe a Jack Dempsey> 10'', 2 blue face discus 4'', <... mixed in with these other cichlids?> 2 peacock bass 5-6'', and 1 Pleco 6''. SUMMARY: I acquired this tank approx. the first week in June, I immediately outfitted the tank with 1/4'' round gravel substrate and about 50lbs. of it, i filled the tank with tap water and added the appropriate dosages of "Stress Zyme" and "Stress Coat" both by "Aquarium Pharmaceuticals," and i hooked up and plugged in all of the equipment and let it run for about 5 days. I then added the Oscar, the Arowana, the Parrots, the South American Cichlid, and the Pleco. After two weeks, I added the rest of the fish but at roughly the same time I noticed there was some ich developing on a few fish so I treated the whole tank with "Rid Ich" for a total of 7 days. on about the fifth day of treatment the Oscar developed a "Hole In Head" about the size of a cubic millimeter, accompanied by two grayish lesions on one side of his body, he was also "gasping for air." To remedy this, I did a 40-50% water change, accompanied by the appropriate replacement doses of "Stress Zyme" and "Stress Coat" and of "Rid Ich" I also decided to treat the entire tank with "Metrazol" [for the hole in head] because I was afraid that the other fish would also soon exhibit the internal parasite. <... not really due to a parasite per se, but poor water quality... poisoning from the Rid Ich to boot> Within one day, the Oscar was still gasping for air but his lesions were clearing up and he was becoming his usual active self. On the beginning of the eighth day [of ich treatment, added every day as directed, and the third for Metrazol, yet, only one dosage of treatment (the directions say only one dose but two if necessary) was put in the tank and deemed necessary because there was (visibly) only one fish to treat] I found the Oscar dead, lesions almost healed, but with brown gills. For a side note, the other fish seemed to be absolutely fine. I immediately took out the Oscar and went to the LFS to get a "TetraTest Laborett." RESULTS: Ph= BTW 7.5 &8, NO2-= BTW 1.6 and 33mg/l <!> (It was RED and I'm sure you guys know how broad these things are), Ammonia= 0, GH= 8-9dh, and KH= 2dh. fed the rest of the fish [like I do every morning and every night, careful not to overfeed, followed by a 50% water change of equal temperature (and proper dosages of "Stress Zyme" and "Stress Coat"). <... you don't want to keep adding these...> I noticed though that this time (doing a 50% water change) the fish did not take as well. the Arowana has been quite temperamental and the less aggressives are significantly less aggressive, particularly the South American Cichlid who is generally quite aggressive, has become quite docile by comparison to his usual self. I really need to know what the best plan of action is for lowering nitrates?? <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwnitrates.htm and the linked files at top> can you give me a realistic idea of how much water i should be changing and when? <This is posted on WWM as well, but you have many larger issues... Principally a lack of sufficient filtration and incompatibility> can you tell me if the Ich medicine conflicted with the Metrazol so I don't do it again (it was LFS OK'ed?)? Or anything at all I'm not considering... I have noticed throughout the forums "Bob Fenner" suggested multiple times to stop feeding the fish until Nitrate levels subsided to 0 and I will do so immediately once I get the OK from him for my tank. I know that 50% changes are not healthy especially when the tank is first cycling but it seems that there are always extenuating circumstances. I'm just concerned about starvin' the Ol' fishies. Sorry i don't have a Nitrate reading yet, will be getting a test kit for it tonight. Thanks ahead of time, George Kordopatis <I do wish we could start back at your planning stages here... the BioWheel is insufficient... the Arowana will get too large, the discus doesn't live in the same water... Time for you to stop buying livestock, medicines, water conditioners... and STUDY. Read on our FW Subweb re set-up, the fishes you list, their care, husbandry, water conditions, nutrition. Basically, start over. Bob Fenner>

High Nitrates in a FW Tank Hello, help needed, I have a major nitrate problem. It has happened in my 10 and 29 gallon tanks and each time I have moved lately it has happened to them (totaling about 5 times). I have been changing the water weekly trying to fix it, but after a few days it is dangerously high again. I have lost so many fish that I am starting over again. I don't want to give up, but in the past I have had a stable tank for weeks, added fish and then it becomes dangerous again in a matter of a few more weeks. How long should I have a stable tank before I add fish? What can I do to increase my chances of getting it started better this time? I have had very stable tanks for 5 years using well water and moved a year ago and have not had a stable tank ever since. Could there be a link? Please help! Thanks. Kris Barker < I would recommend that you do a complete analysis of you tap water to find out where you are chemically. You can ask you local water company supplier for that information. They usually send that to you once a year anyway. Look at the pH, hardness and the nitrates. Some fish don't tolerate extremes in water chemistry. Many agricultural areas have high nitrates from years of over fertilization. I would do a 30% weekly water change, clean the filter and vacuum the gravel. Watch the amount of food you are feeding your fish. Feed them once a day and only enough food so that all of it is gone in two minutes once each day. Before doing a water change I would fill up a 5 gallon bucket the day before and treat it with a chemical to neutralize any chlorine and chloramine. Ammonia and nitrites should be zero, Nitrates should be under 25 ppm for most fish.-Chuck>

High Nitrates Hello, I know there have been questions like this but I am confused. I have had 120 gallon freshwater tank running for over 2 years. It is a community fish tank. I have usually tested my water once a month or so and regularly done water changes at least once a month of 20-40%. I have never had any problems with Ammonia, PH, Nitrate or Nitrite as I try to add things gradually. I have a sand bottom, a Magnum 350 canister filter, and a whisper power filter. I am considering adding another canister but wanted to change the substrate and see if the whisper and magnum would be enough first. About 2 weeks ago things started to go wrong. I performed a water change, 25-30% and I added some gravel (20lbs) and some water clarifier (Tetra brand I think). I added a few more fish (4 guppies, red tail shark, and 3 mollies) over the course or 2 weeks. I have been watching for any ammonia and not detecting any. Suddenly my Nitrates are going out of control (over 160ppm). I performed a 50% water change and repeated the test the next night and still over 160ppm. What can cause such a high spike with no detectable ammonia, and what should I do to reduce this? I did also check my tap water to make sure there are no detectable Nitrates. I am going to keep trying water changes, but was not sure if there was anything else that could be done. I have had about 8-10 guppies die in the past week and a half, and also 2 of my 4 clown loaches that I have had for almost 2 years, and don't want to keep killing fish. Thank you for any help or suggestions, < High nitrates are definitely a problem. If they are not coming from your main water source then I would recommend that you service the filters, remove the rocks and vacuum the gravel while doing a 50% water change. Treat the new water with Amquel plus to help detoxify the nitrates.-Chuck.> Jason

Re: High Nitrates Hello again, I took your suggestions and have done 3 water changes of 50% in the past week and have been vacuuming the gravel each time. I have changed the filter materials. I have also been adding Amquel plus and have not seen much of if any improvement. I have moved everything in the aquarium to ensure I am vacuuming out as much as possible. I have continued to check my ammonia levels and nitrite levels and not seen any registering amount of either. At this time I have 2 guppies, 2 clown loaches (3 inches each), a ghost knife, 2 Neons, 3 algae eaters, 2 iridescent sharks (5 inches each), a red tail shark (2 inch), and 4 white mollies (2 inches each). I have had this 120 Gallon tank setup for 2 years and was not having a problem with this until recently. Is there anything else I should do to try and correct this? < Sounds like you have done everything possible to remove the nitrates from the tank. Now check you tap water. Check it right out of the tap and check it again after it has sat for 24 hours. If may be a change in the water supply. In areas of high agricultural runoff the nitrates leach down to the aquifers and rivers and it could be coming out as high as 50 ppm. Other sources could be decaying wood with lots of cracks that could have been filled by mulm.-Chuck> Thank you, Jason

Re: Nitrate too high Crew, <Frank> As I was changing the water and cleaning the contents of the tank I discovered the source of my water problems. I found a dead Goldie inside a sea shell. He was probably in there for several months. Based on this new information would you revise your recommendation below? Thanks again, Frank <I would revise the advice... I would not raise temperature... but do a good 30-35% water change... wait a few days and do another... and so on... WITH water testing for nitrate and likely ammonia... diluting the former... Do chuck the shell... too likely to cause further troubles. Bob Fenner>

Re: Not sure if treatment is needed, nitrates in source water Bob, Thanks for your response- I appreciate it. I have attached a interesting tidbit I found regarding Nitrates in drinking water, my site is on the list for violations- Yay... http://www.ewg.org/reports/Nitrate/NitrateContam.html I do know I have tested with the Aquarium Pharm. liquid reactants test and have come up over 10 several times in the past- I do not regularly test my incoming water anymore for this. <... and I do think the Fed. limit for nitrate has come down since this note (1996)> I did go out and get some Prazi (Jungle parasite Clear) as it was the most gentle multi-parasite killer I could find, and have started adding salt to the water to get it to .3% for a couple weeks- just in case somehow I got an invader. I do have a Betta in a 10gal at home, but all seems well with him- and I can't remember doing anything that may cause a cross-over contamination. <Unless you introduced "something" live... food/s, plants, other fish livestock... where would this vector from?> I was feeding Marineland's Bio Blend, and Spirulina flakes- supplementing with Cukes, oranges, seaweed, or freeze dried blood worms as treats a couple times a week. I am now just feeding him Jungle Anti-Bac food and will for a good 10 day stretch. I soak all his dried food first to soften it. He is passing the food within a hour of feeding him, and it seems to have more fiber-bulkier feces. <Wow, I'd give your fish the name of Riley, as in "the life of"> With the addition of the meds and salt he seems to be perking up, and acting a bit better- I was worried as I really thought he was on his way out. Am I correct that if it were parasites, between the salt and the Prazi treatments- they should be knocked out? Thanks for the help, and the resources on the web! <Yes... do know that goldfish, and many other fishes do "just go through" bouts of inactivity, lethargy at times... as do I! BobF> Re: Not sure if treatment is needed Aha! Plants! I had ordered live plants a month or so ago- (and sorry to say- added w/o dipping them in PP) Wonder if something rode in on them and set up shop in my fish. <Ooooh> I will never add live plants w/o doing the dip on them ever again! Yikes, oh well- lesson learned- plants are probably not going to survive the salt anyway. They are (were) just a few javas, not nearly enough to battle my little swimming nitrate factory anyway. Thanks for the help! <Good response... actually Java Ferns are quite salt-tolerant... Upward and onward (Excelsior! As Don Dewey used to write). Bob Fenner>

Nitrates in a 10 gallon freshwater aquarium Hello, My husband and I set up our 10 gallon aquarium about a month ago and have a concern over the level of Nitrates we have in our water. The tank itself has sand for substrate, live plants, river rocks and a resin cave rock We have the filter that came with the kit, a heater. Currently we are housing three female bettas (it has been an interesting time and one will be put in isolation due to aggression issues), three neon tetras, one gold molly and two snails (that we can find the stowaways!). We had two black mollies but they succumbed to illness and we had to put them down. We do a 10 % water change every week, scrubbing the tank and creating fish panic while we try to keep their water clean. The tank is clear and not cloudy and the plants are doing well. We have a bubble wall and 10 gallon air pump to oxygenate the tank. We feed the fish twice a day using flakes in the morning and blood worms at night. On to my question: We have purchased a freshwater testing kit and my husband has tested the water in the tank. The ammonia is 0 and the nitrites are 0 but are nitrates are between 60 and 80 ppm. Our pH is 7.2 to 7.4 (which we are treating with ph Down to help out the tetras). With that concern we tested our tap water through the Brita filter we use to drink from and change the fish water and discovered that the tap water had the same nitrate level. My husband (the mad chemist from all the testing) also tested our tap water without filtering it through the Brita and received the same result. After researching your site (which is very informative) I couldn't find a solution for anyone with a tank lower than 55 gallons. I did find a post about acquiring a reverse osmosis machine (see below, and will have to investigate this further if we can't figure another solution). What can be done for us small guys who have nitrate issues? < High nitrates can be a problem for those aquarists living in areas with lots of agricultural activity. Excessive nitrogen fertilizers leach down into the water table and are picked up in aquifers used for drinking water. Many fish cannot tolerate these high nitrate levels. Your best bet would probably use purified or bottled water for your aquarium. R/O will remove most nitrates but I cannot justify buying an entire R/O system for 4 gallons per month.-Chuck> Thanks for your time. Wendy

Located information. "Nitrates in Tap Water Dear Mr. Fenner: <Bob is off in Australia right now leaving the rest of the WWM crew to pick up the pace.> I have a 135gal tank with African cichlids in it. They are all doing wonderful. Have even had Kenyi produce fry, and Jack Dempseys also. My question is the Nitrate level is always high. Have tried placing reducers in the canister filter, but it really doesn't help much <Not very cost effective either.> so last night I set some tap water out....and tested it this am........and found my problem......the Nitrates are high 50-110ppm in the tap water. <Wow.> What can I do to reduce them in the tap water before adding this water to the tanks. <The first thing I would do is request a report from your local water authority. By law they have to send you one every few years and whenever you ask. That seems really high. I know there is a federally mandated upper limit, but cannot recall the exact number at this time. Your only corrective course of action is a RO unit. You may want to consider a large unit to produce drinking water, too.> Please help......all my other parameters are great......do weekly water changes.....with gravel vacuuming...but still can not reduce the nitrates. Any suggestions would be greatly appreciated. Sincerely, Shirley <You are welcome. -Steven Pro>"

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