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FAQs on Marine Water Quality involving Testing for, Measuring  Nitrate

Related Articles: Nitrates in Marine Aquariums, NitritesAmmonia, Establishing Cycling, BioFiltrationPhosphate, SilicatesNutrient Control and ExportDeep Sand Beds

Related FAQs: Nitrates 1, Nitrates 2, Nitrates 3, Nitrates 4, Nitrates 5, Nitrates 6, Nitrates 7, Nitrates 8, Nitrates 9, Nitrates 10, Nitrates 11,  & FAQs on: The Actual Science Re: NO3 Compounds, Importance, Sources, Means to reduce: NNR (Natural Nitrate Reduction, Anaerobic Bacteria), Algae, Other Biota, Physical Filters, Chemical Filters... ... NitritesAmmonia, Phosphate, Silicates, Biological Filtration, Fluidized Beds, Denitrification/Denitrifiers, Bio-Balls, Wet-Dry Filters, R.O./Distilled/Treated Water Chemical Filtrants Deep Sand Beds

High Nitrate Presence Short List/Equation: Too much source, not enough uses, limiting factors.

Nitrate test accuracy     11/9/13
Hello again Mr. . F
I am using a different message because the topic is different. I need your opinion on this: I have 2 Salifert nitrate tests produced in the same time , they will expire on 2015. They both indicate a bit less than 25 ppm of nitrates on my tank. I have lots of SPS, growing, I run biopellets, have a sump full of liverock , the famous basement refugium with 18 cm of DSB and Chaetomorpha that we were talking about ( 3 weeks old though ) and a skimmer rated for twice the volume of water that I employ ( AquaMedic ACone 3.0 ) .
So a friend sent me the new Seachem nitrite/nitrate test, brand new. I do the test and surprise: less than 2 ppm of nitrates. This particular test has a reference solution so I used it with the Salifert test: another surprise: even though the test solution was supposed to have 10 ppm of nitrates and was unopened so no evaporation or air contact the same test that said that my tank has 25 ppm nitrates indicated 2 ppm on this one. So I used again this test solution but this time to test the Seachem test, and it showed 10 ppm as it should.
What do you think?
<Mmm, appears that the Salifert kits may well be off... do both measure Nitrogen as Nitrate? OR Total Nitrate?>
On the other side, I attached a photo of one of my Acroporid that shows some signs of very slow tissue lost. Can this be connected to nitrate concentration.
<Could be a variable, yes>
The same Acropora shows signs of growing and polyp extension.
Thank you again,
<Welcome. B>

cycled WITHOUT a nitrate test?     6/12/13
Hi guys,..I'm back!
I know, I can go for months without questions ( I do try to figured things out myself!) but some questions are so simple they can't be found!
Gee, did I just call myself simple? Anyways, here it is;
Is it possible to determine that ones tank has cycled WITHOUT a nitrate/nitrite test?

<Mmm, yes; "bioassays" come to mind... algae growing, fishes et al. not dying>
I ask this because my ammonia WAS at 0.25 for 2 days, and is now barely detectible. I say "barely" because I'm using the API test for ammonia and it is very difficult to read!
<Agreed... good, cheapy kits but more yes/no than measures>
My brand new 75g. system was set up on May 15th.
One more thing , (but of course!)
I've been monitoring the water parameters and tweaking.
These are the numbers thus far
 a.. Mag  1560     a bit high
<Yes... don't add to, increase this>
 b.. Cal   440
 c.. dKH   10     a bit high
 d.. pH     8.4
 e.. SG     1.024
Is dosing NOT a good practice during cycling?
<Unless otherwise really warranted (e.g. precipitous drop in pH), not a good idea>
Thank you to everyone who help me relax into this challenging hobby mais uma vez! (once again!)
<Welcome. BobF>

Re Rejuvenating an "Old" Tank... FO  7/19/11 7/20/11
Thanks a million James.
<You're welcome, Dave.>
Very helpful and sounds like a great plan. I'll get the live rock ordered next week and start the swap out process once everything is cured. I'm looking forward to the new adventure. I checked the test kit (API brand) and it's NO3. So, you're not terribly worried about NO3 in the range of 80?
<I am, you misunderstood my statement. If you got a 80ppm reading with a Nitrate-N kit, I wouldn't be concerned. Your Nitrate-NO3 reading of 80ppm is very high and action needs to be taken to reduce this level. Do read here and act. http://www.wetwebmedia.com/nitratesmar.htm>
Am I over-worrying about this amount of nitrate at this point given what we'll change up (removing the bio-bale and bio-balls and adding the live rock) going forward?
<Removing the biomedia isn't going to lower your nitrate appreciably, just slow down the process.>
Several folks have said that API test kits aren't very sensitive and I should just spend the dough on something more accurate like Salifert.
<I wouldn't be concerned with that right now, the API nitrate kits are close enough.>
Enjoy the week.
<And you as well. James (Salty Dog)>
Dave de San Jose

New Red Sea Nitrate Test Kit   3/18/11
Looks like this may be a fairly accurate nitrate analytical comparator test kit and it looks like they will be etailing for about 35 bucks.
<I do like this video on the use... Straight-forward, clear, complete. BobF>

Water testing... NO3... SW?   2/15/10
Hi crew,
<Hi Pat>
I've been testing for nitrates with API drops, and they show "0" nitrates.
<NO3? Not likely>
I bought 6 way test strips by Jungle Laboratories, and they registered a solid 40 ppm mg/L
Water for both tests was sampled from same location in the tank.
Your thoughts please
<A dodgy test kit. Have you checked the expiry date? Try Salifert for a better, more reliable kit>

Re: coral question, now NO3   01/13/09 Hi Sara M <Hola Tina> Sorry, one last question. Last summer I was having problems with nitrates. After a water change they would be at 10 & then creep up to 20 after about a week & then I would do a water change & they would go back to 10. I asked WetWebMedia for help with this & it turned out my canister filter was the cause, but in the reply I mentioned wanting sps corals & that I knew I couldn't get them until my nitrates were at 0, in the reply I was told that I was not supposed to try for 0 more like 5. <There very few concrete "rules" about these things. Truth is, you might be able to keep some SPS corals with nitrates at or below 5, but there might be others who just won't tolerate it. In either case, even if some of your SPS frags might tolerate the nitrates, they likely won't be as healthy as they would be with nitrates at 0.> In the display tank I have 2-4" clams & unless I have been reading your site wrong I thought they needed some nitrates for food, so I assumed when I was told to keep the nitrates closer to 5 that the sps would use some nitrates for food also. <The thing is that what you're measuring with your test kit is "excess" nitrates. The nitrates that the animals might be metabolizing won't stay in the water column and so won't show up in tests. So you want your measurable nitrates to be as close to 0 as possible since what you're measuring is not any and all nitrates, but excess nitrates. Does that make sense?> I have been using the display tank water for the hospital tank thinking the sps would use the nitrates. So if they don't like nitrates & the clams do need some nitrates, then am I wrong in thinking the sps will never mix with the clams, or is it just the birdsnest corals that won't tolerate the nitrates? <Please see above. Your tank will *always* have nitrates. What you don't want is excess nitrates.> Confused again! lol <I hope this helps.> thanks a bunch Tina <De nada, Sara M.>

Re: Hair algae suddenly growing in Refugium  1/25/08 Thank you again, I guess I needed reassurance. Anyway amazing what 2 Turbo snails can do overnight.... I'd say they plowed through about 65% of the hair already... another day or two and it will probably be all gone. One other quick question if I may... your opinion on which Nitrate test you would believe is more sensitive. I am using the Instant Ocean Nitrate test as well as the Aquarium Pharm Inc. The IO measures out at 10 but maybe a bit fainter but lets call it 10, the API is measuring 20. I am taking the average and assuming 15. Thanks again. <Of the two, I'm more a fan of the (Hach-repackaged) IO... but do encourage you to seek out other lines... If interested: http://wetwebmedia.com/mtestbrands.htm and the linked files above> PS. loving the invert book started the refugium chapter....wow what a great resource! <A fine opportunity to put our ideas in print. BobF>

This one's got me!! Nitrogenous test kits  -- 06/07/07 Crew, <Michael> I have had a 20 gallon saltwater system set up for about 4 months. I ran into a problem about a month ago with high nitrites and nitrates. I moved the livestock to a QT tank and most of them made it (didn't have much since I just started, just 3 clowns, <Better to just have two... a third will be brutalized in time...> 1 flame angel <... not enough room for this species here> and one red mushroom remain) I know, the flame angel will eventually go to a 200 g when we finally get that going, hopefully soon). <Wait till then> At the time I decided to upgrade the 20 g and install an internal overflow and hard plumb it to the 10 gallon sump below. <Good practice> Finally got that done about 2 weeks ago. For equipment I have the 10 g sump, a 4.5 g hang on back refugium with miracle mud and Chaeto, a Remora skimmer and about 25 lbs of LR. When I set up the new system I put in a new substrate of CaribSea Arag-ALIVE. The LR is fully cured and when I set up the new tank, I used about 16 gallons of water from the QT tank (55 g) to get the 20 g tank going again. Since I had a new substrate I figured the tank would have to cycle again. <Likely so> I have been testing everyday with Salifert test kits and it has shown Nitrites .5 - 1.0 <Hopefully sans livestock presence> and Nitrates 5 - 10. Getting low on those test kits, I found a Hach Saltwater Master test kit direct from Hach for $58 which included 50 tests each of Ammonia, Nitrite, Nitrate and pH (what a steal I thought). <...!> Got the new tests yesterday and of course had to try them out. The Hach test kit shows undetectable amounts of Ammonia, Nitrite and Nitrate on the 20 g. Being puzzled, I did the same test with the Salifert kits which showed Nitrites around 1 and Nitrates around 10. So, I did the same testing with the QT tank. Same results, Hach undetectable, and Salifert show Nitrites 1 and Nitrates 10. Trying to get the bottom of it, I decided to test my pre-mixed saltwater which I use RODI water with a TDS of 1 and Bio-Sea Marinemix which I just mixed it last night. Hach shows Ammonia, Nitrite and Nitrate undetectable, and Salifert shows Ammonia 0, Nitrite 1 and Nitrate 5. So, is the pre-mixed salt water supposed to be 0 for Ammonia, Nitrite and Nitrate? <Yes, though some will show nitrate and some do register some ammonia initially> I assume it should be since there is no bioload. I just want to make sure my new test kit is the "bomb" before I return my livestock to the 20 g display. Do you think my tank is ready, or should I wait until Salifert shows I have 0 Nitrites (which could be never). Michael Svehla <I would "check the checker" here... take both kits to a dealer, have them test their water with them. I read the Salifert's as being off here. Hach is a MAJOR manufacturer of many other companies' reagents... Bob Fenner>

Aquarium Pharmaceuticals Nitrate Test Kit, Total Nitrate and Nitrogen as Nitrate...   6/6/07 Hi Crew, I hope this post finds you well and in good spirit. <Thank you Brad> Having read previous postings on "Aquarium Pharmaceuticals Nitrate Test Kit" here at www.wetwebmedia.com I must admit that I am still confused. My confusion is most likely self induced because sometimes I have difficulty grasping general or basic chemistry and how it relates to our hobby. <Let's see if we can clarify, bring these concepts in line with your present understandings> With respect to Aquarium Pharmaceuticals the following paragraph was copied from "Aquarium Pharmaceuticals Saltwater Master Liquid Test Kit" instruction booklet. "This test kit reads total nitrate (NO3) level in parts per million (ppm) which are equivalent to milligrams per liter (mg/L) from 0 ppm to 160 ppm, in either fresh or saltwater aquariums. This test kit measures nitrate ion or "total nitrate." Other nitrate test kits that measure "nitrate-nitrogen" (NO3_N) will give readings 4.4 times LESS than this test kit." <Yes... the "other" kits referred to are taking into account the O, Oxygen in the Nitrate (NO3)...> Using this test kit I observed a NO3 test result of 100 ppm on all three of my tanks (two twenty gallon and one seventy-five gallon). Our tap water measured a NO3 level of 5 ppm with this test kit as well. My two questions are as follows: 1.) When anyone on the "Crew" makes a nitrate ppm recommendation is it based on NO3 (total nitrate) or NO3_N? <For me, Total Nitrate> 2.) By comparison, what does a NO3 ppm measurement versus a NO3_N ppm tell us as aquarists about our water? More specifically is there any benefit to knowing both NO3 and NO3_N ppm levels to the health of our tanks inhabitants? <Mmm, good question/s... More to most important to know/understand either measure... as they are for the most part directly proportional in our settings... AND their implications, causes, cures... To do what is reasonable (low stocking, feeding, appropriate filtration, maintenance... countervailing strategies to limit their accumulation. A very nice piece re can be found here: http://www.novalek.com/kordon/articles/KPD63.htm by Dr. Bob Rofen and co.> Many thanks for your continued efforts. Best regards, Brad Kizer <And you for your participation. Bob Fenner>

Re: Aquarium Pharmaceuticals Nitrate Test Kit -- 06/07/07 Hi Bob, <Brad> I appreciate your help. The link you provided was/is excellent reading. Thanks again, Brad Kizer <Ah, good. Bob Fenner> Nitrates, testing Your Mother-in-law lives on Jewel?!? <Yes... and has a place in Belmar...> Wow! Small world! Again, the book is phenomenal. <Glad you are enjoying, gaining by its reading> Yes, the nitrates could be lower but I am not completely certain as to how low or high they really are. I felt the test strips were a good quick way of getting a reading while not removing much (5 gallon tank) water and saving some money (I am forever amazed at each new thing I seem to 'need'). I usually use these strips every other day and then take the water every third or fourth day and use a chemical test to verify. One of the local fish store owners recommended the nitrite and pH test kits from Aquarium Pharmaceuticals Inc. He seems more on the minimal side as to how much you really need to enjoy the hobby. <I am in agreement with this philosophy in practice> The test strips are from Jungle Laboratories Corp and I got them through the Dr Fosters Smith website. Perhaps I will invest in a more accurate nitrate test kit.  <The cost per test with colorimetric solutions is quite small... turns out, less than strip testing> Thank you so much for responding to my email. James Zimmer Garfield, NJ <And you for yours. Bob Fenner>

Nitrate test kits 7/25/05 I have been caring for saltwater aquariums for many years now and have recently (about two years ago) started to maintain reefs. I have used a variety of different test kits from dry tabs, to liquids, to strips. I know that it probably depends on the brand but which kind is considered "the best" or the most accurate? <I like Aquarium Systems test kits.  Reasonably priced and reasonably accurate for our needs.>Also, I remember reading something about multiplying the number you get by three or four or something like that to get the true nitrate level. It had something to do with what the test kit was actually testing for. Do you know of anything like this? <You need to know what the test kit is measuring, nitrate as an ion or as nitrate nitrogen.  Total nitrogen is the result of the 4.4 multiple.> I am very confused on that subject. Now any time I get a reading of any nitrate I feel that it is to much especially if a reading of ten really means forty.<For our purposes, a reef tank should not exceed 20ppm of NO3-N.  For fish only 20-40 is acceptable for most species, although we don't like to keep nitrates that high as they do increase nuisance algae growth.  Hope this helps.  There are FAQ's on this subject on the WWM, keyword "nitrate testing".> Thank you for your help, Andy <You're welcome.  James (Salty Dog)>
Re: Nitrate test kits 7/28/05
Even after I find out from the manufacture what the test is testing for, the question still remains. Do you multiple by 4.4 if the test is testing for nitrogen ions or do you multiple by 4.4 if the test is testing for total nitrogen? Thanks, Andy  <Total nitrogen.  James (Salty Dog)> <<What? RMF>>

Nitrate Test Readings, Bob's go 7/28/05 Hello wise wizards of the wet watery world (please forgive the alliteration): <Monstrous, but okay> After reading both the article regarding Nitrates and the numerous FAQs that address this topic, I would like to impose upon you to clarify my confusion, hopefully once and for all.   <Go ahead> I use the saltwater master test kit made by American <Aquarium> Pharmaceutical. I went on their website and confirmed that their nitrate test kit measures the nitrate ion. My reading using this test kit has been consistently around 60 ppm. Now, if I correctly understand the article, I need to divide this result by 4.4 to arrive at 13.6 for nitrates as ppm. So, are my true nitrates only 13.6 ppm as opposed to 60 ppm?   <Mmm, not to be disingenuous... but if the measure is stated by AP as nitrogen in or as nitrate... you would actually divide... but I suspect you actually have about 60 ppm of nitrate> As always, your sagacious words of wisdom are eternally appreciated. Regards,    Mitch <... think about what you're measuring, the molecular weight of nitrogen, oxygen... nitrate ions as NO3... stoichiometry... Bob Fenner>

Re: nitrate problem solved for now 10/25/05 Hi, A short while ago I wrote about fouled DI resin and high nitrates. Well Bob was right, the test kit I was using measures high range and low range nitrate. I was reading the wrong side of the color indicator chart.  My nitrate levels were really at less than 50ppm. I have performed numerous water changes of 30 percent and now my nitrates are down even further. I made a Denitrator coil to bring them down a bit further. I have a light bioload only 3 shrimp, 1 starfish 2 LPS corals and 3 small fish in my 125 gallon. " Well here is my question. When should I see results in nitrate drop from this coil? <weeks, months....dilution is always the solution to nitrate problems> I know they have to cycle and can take weeks. I have a very slow drip just short of a stream coming out of it. Do you have any experience with these or heard of any good results from using these DIY denitrator coils.  <have heard some success stories> I know they are no substitute for replacing trace elements during regular water changes. <agreed>  I also wanted to ask about calcium levels. My level is at 450ppm and has been there for a few days. I was under the impression that it is absorbed rapidly. <yes...by clams, LPS, SPS, etc>  I am adding F.O.R.M and Kent's buffer once a week. My coralline algae is amazingly dark and purple. Thanks for your advice.  <everything seems to be going fine, good luck, IanB>

Testing the Tester (5/16/04) Hello Crewperson: <Steve Allen tonight> I am curious about testing my Nitrate tester. Aside from comparing to another test kit, is there some way I can make a solution known to contain nitrates (in lieu of mixing one part Nitrogen with 3 parts Oxygen :o), to see if my test kit responds? <I am not aware of any way to do this. You could check with your local water department. I'll bet your tap water has nitrate in it. They can tell you about how much and you can test that way. Your best bet is to be sure to use a top-quality kit such as Salifert, Hatch or LaMotte.> Thanks, Rich <Hope this helps.> 

Nitrates (11-5-03)  Hello,<Howdy, Cody here today.>  I have a 90-gallon fish-only with live rock marine system with the following set-up.  Wet-dry filter w/bio-balls and additional 20-gallon overflow. Protein skimmer, UV-sterilizer, 3 power heads in tank for additional flow, HOT Magnum filter (that is only used as a water polisher a few times a year).  The tank is currently stocked with only 3 fish, a large yellow tank (6 inches), a large miniatus grouper (6-7 inches) and a medium Picasso trigger (4 inches) -- the tank contains about 65 lbs of live rock and about a 4 inch base of finely crushed coral.   I purchased the system about 3 years ago and used the knowledge that I gained from reading your website and a colleague (marine biologist) at the university to set the tank up 'successfully'.  Over the past 2 years, I've had a few trials and tribulations stocking the tank -- but have only lost a couple of fish (generally because the grouper and the tang attack anything that is added to the tank).   All 3 of these fish have been in my tank for about 18 months and appear rather bullet-proof (including surviving an Ammonia outbreak 12 months ago caused by my wife using Windex to clean the tank'¦. She has since been issued with a 10 ft restraining order from the aquarium).<Glad to hear they made it!>  My current water levels are as follows (tested today): pH 8.1-8.2, ammonia 0 ppm, nitrite 0 ppm, nitrates 30 ppm, SG 1.023 and total alkalinity of about 280.  These values have been stable for the last 6-7 months, and rarely fluctuate.  Obviously, the nitrate level does increase over the course of the weeks, but I find that doing a 25-gallon water change every 3-4 months keeps it down to 20-30 ppm. In the beginning, I used to change the water 5%-10% every 2-3 weeks and found that I was losing fish on a regular basis. Often, it was very visible that their slime coat was being removed and looked like they had spots all over them. Initially I thought it was a disease, but the marine biologist at the local university (who has been a marine aquarist for 30+ years) came to take a look and informed me that the 'spots' that I thought was a disease was actually being caused by the fish losing their slime coat, and the 'spots' were tiny particles of debris in the tank (food, sand etc) attaching to the skin of the fish -- causing much stress.   I was instructed by my colleague to reduce the frequency of the water changes and this totally solved this problem and, as I mentioned earlier, the only fish I have lost in the past 6 months were a yellow wrasse and coral angel (both eaten by grouper). The more frequent water changes were actually causing stress to the fish as a result of a continuously changing environment.  My question to you is in regard to the nitrate levels. Many, many people write in to your website, reporting 0 nitrates? How do they do get this reading, or should I not believe that this is the case. I am a professor of chemistry, and understand the nitrogen cycles in biological systems -- but cannot fathom how aquarists can maintain a reading of 0 ppm nitrates, since it's the final product in most of these continuous cycles. For chemistry research purposes, you can purchase nitrate absorbing columns, but these are generally very expensive (in excess of $800 per column) and also remove  chloride, phosphate and some carbonate ions -- so probably shouldn't be used in a marine aquarium. Theoretically, nitrates are always going to be produced (by appropriate bacteria) from waste products like ammonia, some proteins etc. Is there a way to reduce nitrates effectively, other then skimming, plants and water changes?. My understanding is that plant life can control nitrate between 30-40 ppm, but not any lower. Obviously water changes dilute the nitrate levels, but it seems to be quite problematic to the livestock to perform several changes over a short timeframe.   Or is 30 ppm nothing to worry about? I have been told many differing opinions on this. Some enthusiasts claim 10ppm is the max allowed, some say 150ppm isn't a problem for fish-only systems -- what is the truth? Or is it more a case of -- whatever works for your system.<I would not be worried about 30ppm in FO tank. Many people that have the 0 nitrate have deep sand beds and use a RO machine and once they get past the initial cycle are careful of how they feed, keep up on water changes, running good protein skimmer helps also. The bio balls will also raise the nitrate a bit but I would not worry about it in your case.>  Finally, in the coming weeks, I want to add one or 2 or 3 more fish to the tank. Given the fact that the grouper and tang can be very territorial (putting it mildly) how should I add these fish, and which fish would you recommended to add. My favorite species are the tangs -- are any other suitable for this system. Should I remove the yellow tang and grouper before adding the new fish -- then reintroduce these 2.< I wouldn't add any more fish to this tank. Anything that is big enough to survive will likely put too much of a burden on you filtration. No more tangs this tank is too small! All three of these fish will require bigger quarters in the near future. Better start thinking of some good excuses to get a 180J. Hope this helped, Cody.>  Any help you could provide would be very much appreciate.   Cheers, Jeff 

Nitrate Test Accuracy Crew, A quick question.  I have been fighting Nitrate levels in my tank for some time and have made many changes.  I normally use AquaLab IV test strips from Mardel and get readings of between 20-40 ppm.  Yesterday I tried a different testing procedure from Red Sea Fish pHarm and received readings of Zero.  I repeated the process and again received a Zero reading.  I would not be surprised to find that the Nitrates in my tank are now under control since I have added a sump, upgraded the skimmer to an Aqua C Urchin pro, and have been very careful feeding.  Long story, but my question is how reliable are the test strip products verses the test tube type that use regents?  Given the crews vast experience, how should I feel about the Nitrate levels in my tank given the disparate readings? <Hi Bryan, sounds like you have a nice setup. I would guess that the strip tests were the problem. I would recommend one more test (reagent based) maybe from a friend or a LFS just to confirm the Red Sea tests. Don> Thanks! -Bryan

Marine testing Dear Bob, <Anthony Calfo in your service> I have kept marines for over 5 years now but I have a problem with managing my nitrate level, this may not be linked but I am also plagued with red algae.  <indeed... both are associated with high nutrient levels (lack of daily protein skimming, overstocking/overfeeding, etc> The red algae appeared after I bought some rock from a friend of mine - the algae now predominates to a point where virtually no green algae will grow. I water change every two weeks (roughly 20%)to keep this down but if left it will spread over the crushed coral sand and the glass where it appears as a dirty brown covering. <good water change schedule... you may simply need better performance from a skimmer (getting 4-8 oz of dark skimmate daily to prevent such nitrate and nuisance algae> At every water change I check for ammonia, nitrite and nitrate, the ammonia and nitrite are virtually 0 but the nitrate is somewhere between 25-50ppm (the test kit is not too accurate), I'm sure this is why I have problems with inverts, especially anemone's. They appear to thrive after going in, e.g. feed well, move around, strong color, but after a few weeks they begin to go downhill and look sick, e.g. flaccid tentacles, stop feeding, loose their color and most eventually die.  I suppose my major problem is my nitrate level but I cannot get this a manageable level even if I water change weekly - I just put three tubs of Tetra's nitrate minus in last week (between the calcium plus and the coral sand) but as yet with no effect. I work in a chemistry laboratory in the University, so have access to general reagents, I spend a fortune on test kits so I wondered if you know what chemicals are used to test for nitrate, all our methods require spectrophotometers. <I cannot offer advise here... will defer to Bob> Any advice you have would be gratefully received - Kind Regards Jeremy <best regards, Anthony>

Nitrates quickie question Hi Guys <Cheers, dear> Just a quickie - we cannot get an accurate reading for nitrates in our marine tank. Currently we use three - a tab test, powder and liquid. The results are: Tab test - 100ppm + Powder - 50ppm Liquid - 10ppm! Quite a difference! All tests are relatively new. Which would you rely on? <well as a rule, dry reagents are more reliable and longer lived (shelf life) than liquids. Have you checked the dates of all reagents to be sure that they are fresh? Also know that test kits may read nitrate as an ion or as nitrate-nitrogen and there is a difference of 4.4 with the multiple. So.. a reading of 10ppm with a multiple factored in could very well agree with the 50ppm reading (one in the same). Do read your test kits more closely to determine what form of nitrate they are actually reading and if the reagents are actually not expired> Thanks Lesley <kindly, Anthony>

Can't lower nitrates Hi Bob, I love your book. Superb illustrations. <Thank you> After much research I am still having problems with nitrate levels. I sure hope you can assist me. <I'll try> My tank FOWLR and a few inverts is a 55 gal that has been running for almost one year now. I'm using the same brand of test kit (JungleLabs) and have tried a few new sets in case one got messed up. I've also tried a powder kit (sorry, can't think of the name). When the tank cycled Nitrates started low 5 to 10 ish. They have progressively got worse and worse. I've added Caulerpa, more rock, and recently added AZ-NO3 which claims to get rid of nitrates in 30 days. It didn't work. It did bring them down from 80 to 100 to about 40. ( the powder kit says the nitrates are 10 to 20) Sad, but I'm real excited about that. For specifics I have a AquaC urchin skimmer in a 10 gal sump. I'd guess about 90 lbs of rock. About 55 lbs of substrate ( like 2 inches worth). I've added a huge wad of Caulerpa. The fish are 1 yellow tang ( about 1.5 inches) a Pacific blue tang ( about 1 inch ) two percula clowns ( less that 1 inch each). 2 Sand sifting stars, 1 cleaner shrimp, 1 camel back shrimp, 1 peppermint shrimp. A handful of hermit crabs and Astrea snails. 1 sea urchin. I do a 20 % change weekly. After the change I see NO difference in the reading.  <Would you please test the source water with your kits? I am suspicious... not of the tapwater, but of the assay devices> I have a R/O system, but only get about a gallon a day - after the wife and kids. So I get water form one of those water dispensers at the grocery store - Glacier brand. I've tested those sources for nitrates and it shows none. <Oh? Does it seem odd to you that you're diluting the tank water by a fifth, yet not registering a commensurate drop in nitrate concentration? It does to me> I've even tried a LFS that sells salt water - with no adjustment in nitrates after cleaning. I usually siphon the water without disturbing the bed except to pick up big things. In the past year I've vacuumed the bed once. One side one month, one side the next month. More about the tank. I have a penguin bio wheel 300?? (dual wheel) filter. After reading about bio wheels being nitrate factories I pulled them. AZ-NO3 mentioned pulling poly bags, and I recently pulled the pads - so that filter is essentially circulating the water. Feeding. I give them 3/4 cube of Formula one or Formula two. I tried cutting that back and someone started eating the hermit crabs and snails. ( I think I am missing a shrimp too). So now I have an automatic feeder that gives them a pinch of flake formula two ( algae) in the am, and their 1/2 to 3/4 cube at night. One of the shrimp has molted 3 times, and they all look content - although I do see a big increase in activity since the AZ-NO3. I tried e-mailing those guys and haven't heard back from them. <Unusual... MMM/Marine Monolith Monsters are fine fellows... perhaps they've been on vacation...> I hope I've covered everything. I really hope someone can shed some light on my problem. It's a sickening feeling not being able to help the fish and control the environment, and almost makes me want to go back to fresh water. One last tidbit - Tank is by a window, but never gets any direct light. My lighting is one of those "Glo" tubes - the one with the highest temp. I turn on the light about 6:00 pm and it goes off at about 11:00. <Shouldn't be a factor here> I should mention about the AZ-NO3. My skimmer ( which I added to my setup about 3 months after I started the tank) went into over drive. I cannot keep up with it. I clean it daily, but when I get home the sudsy crap has oozed out and all over the sump. Before AZ-NO3 which was into the just this month, I has really not getting much of anything out of my skimmer. <Ahh... a useful clue/insight> Could all this be from that missing shrimp? He was only about an inch and a half long. If so, how long can I expect the effects of his death to linger on? <No, but the loss of the animal and accumulating nitrates are likely linked...> I'd like to hear your thoughts on using ocean water for water changes. I live in Monterey, CA. It is a marine sanctuary. I got a sample yesterday and tested with every test I have. PH, nitrate, salinity, Ammonia. All were perfect. The reason I'm bringing this up is because, people keep mentioning my water as the source ( but like I said, I test it before I add it and it shows 0 nitrates). <In general not worth the effort... to store, clean... buffer... Please read here: http://www.wetwebmedia.com/seawater.htm and the FAQs linked> Thanks for your time, MikeG <Now, re the root cause/s at play here. Do test your alkalinity... I strongly suspect it is dangerously low... this, and/or a serious imbalance of two alkaline earth elements (Calcium, Magnesium) are out of balance (about 1:3) would explain all the above cleanly (including the loss of your shrimp). Do take a read through the sections posted on WetWebMedia.com re the issues. Bob Fenner>

Re: Can't lower nitrates Hello Bob, Thanks for the prompt reply. Until today I thought an alkalinity test was a PH test. I got a kit on the way home and tested the tank. It read 2.2 which converts to roughly 6 something. From my reading today, that is just about right. <Actually, a bit low... 8-13 meq/l would be better> That test kit was a Red Sea. It measured both pH and alkalinity. The PH test read 8.6 where as my usual test (tetra) reads 8.0. This bugs me and got me thinking. <Me too> So I got a Aquarium Systems nitrate kit (powder) and that one tells me my nitrates are just above 10. My LFS uses Jungle Labs test kits, so they will probably show me the same results as my kit ( my 3rd kit ) of 40 ish. <No... that Junkle test kit is off> I also tested the source water and it registered 0 nitrates. <As it should> Are there any other tests I should try? You mentioned Calcium and Magnesium. <Calcium might be of interest, use... especially should you "get into" biomineralizing life (e.g. stony coral) culture> Do you know of a source that I could send a sample of my water to for a complete/better evaluation? <Not really "send away"... as the sample can/will change over time for many variables... I would be satisfied with "checking the checkers" with other reliable test kits... For now, re nitrate, pH, I wouldn't be concerned. Bob Fenner> Thanx again, Mike

Ok I give up...aarrgh! (Nitrates...) Hi! Thanks for taking the time to read this. <No problem.> I have a 55 gallon tank with a 6 inch Porcupine Puffer and 4 inch Yellow Tang. I have 35 lbs. of probably not live anymore rock and 1 inch of aragonite substrate that is 4 years old. I'm running a CPR Bak-Pak skimmer with bio media along with 3 powerheads (one with a quick filter) for water movement. I recently transferred a 33 gallon tank to this new size. These questions would have been the same if I didn't buy the new tank. As for lighting, a 96 watt compact flash canopy with a 10,000 and an actinic bulb. My problem? Nitrates! Always have been high. We're talking in the 160 ppm range....yikes! <Yes. Yikes!> All other readings are fine. <Really? I would be very interested in your pH and alkalinity.> I've tried the 50% water changes, praying, screaming but to no avail. I feed the fish once a day. The Porcupine has lived in these conditions for 3 years. <A very tolerant fish, but was your Yellow Tang shown any symptoms of poor water quality; getting paler or the beginnings of Head and Lateral Line Erosion?> When I transferred the old 33 gallon of water to the new tank and over a week added the 22 other gallons of clean water, the nitrate was still 160! <Check a few things, one test just your source water (tap, well, whatever) for nitrates, then next test your new saltwater. This will tell you if you problem is from the source water, slat mix, or confined to the aquarium. Also, have a sample of your tank water double checked at your local fish store to make sure your kit is accurate.> Should I maybe remove the bio media? <Maybe, but this will not effect a cure just yet.> My pH is also a little low (7.7- 8.0 ish). <As I suspected it maybe.> Can that be that the substrate is old? <No, you are probably not doing enough of large enough water changes or your source water is contaminated. If your nitrate is 100 ppm and you do a 50% water change with water that has zero nitrates, the best you can hope for is lowering the level to 50 ppm. If you are not seeing a difference with large water changes, something is amiss.> Should I just buy a dog instead? <I have tanks and a dog.> Thanks a million... <Good luck to you! -Steven Pro>

Nitrates Dear Bob  <cheers, old sport. Anthony Calfo in your service> Thank you for answering my query about my flame angel so quick. I have another query about Nitrates (many apologies if this is like so many other queries you've already had about nitrates). My tank has various soft corals including Sarcophyton, button polyps, green star polyps etc, and live rock in it, the stock is thus :-  1 regal tang (you guys call it the hippo tang)  1 rainfordi goby (sand sifting species)  1 Banggai Cardinal  4 percula clowns  1 flame angel  1 midas blenny  My Nitrates are 25ppm (phosphates are zero), your book seems to recommend 10ppm or less, and I have had it down to about 10 to 15 from time to time. Hair algae is only present in a few isolated tufts, and purple corallines are growing well.  <nitrate can be measured as nitrate-nitrogen or as an ion. The actual nitrate level on most test kits is a multiple (4.4) of your given reading. As such, your 25 ppm is actually over 100ppm. You have hardy creatures, however, and have noticed that things are relatively fine for now. However, many inverts and some fish such as the Angels, butterflies and tangs will almost suffer certainly in time from exposure. Do aim for under 10ppm> My mushroom polyps are splitting and spreading, and my button polyps are growing very well, <exceptional among reef creatures in that they like lower light and higher nutrient environments> as are my soft corals. 25ppm to me is much easier to manage. Is this an acceptable level for the stock I have in terms of corals and fish? Or is 10ppm a strict figure to achieve?  <try another or better skimmer that produces a lot of skimmate daily to spare you excessive WCs to keep the nitrates down> Cheers, Jim  <kindly, Anthony>

Nitrates still out of control Hello again, First, just wanted to throw a very cool link your way... very big news (no pun intended). I'm sure you probably already heard / read of this, but just in case: http://dsc.discovery.com/news/briefs/20020225/squid.html To update you on my tank situation: we have emailed each other a few times on my nitrate problem. Okay, 'problem' is entirely too gentle a word. I have turned my sump from a wet/dry filter into a refugium. It has about 2" of aragonite for substrate, a bunch of live rock rubble, some hermits and a few snails. There is a small LOA PC unit on 24/7. I finally got my hands on some Caulerpa (prolifera, I believe it to be) and MAN did this stuff take off. If this was my yard, I'd be panicking, wondering how I was going to get rid the stuff. Seriously, looking at it in the morning and then again in the evening when I return from work, I can see noticeable growth. I also replaced all my old crushed coral substrate with a three inch bed of Southdown. After doing this, I did three water changes- the first was my scheduled water change, the other two were to try to help clear the tank a bit. In the span of a week, I'd say I did about a 50% change. It has now been two weeks, and I tested my nitrates this morning. They are still... well, my kit doesn't even begin to approach how high they are. If I had to guess, I'd say probably around 72,874 ppm. Give or take a few tens of thousands. ;) The tank is a 55 gallon FOWLR... well, a few inverts. Hermits and snails, two featherdusters, and quite a few mushrooms. The piscine inhabitants are a yellow tang, a regal tang, and a false Percula. I feed very sparingly, mostly for the Percula's benefit, as the tangs both seem very happy to graze on the hair algae (though that's been dying off rapidly since the introduction of the Caulerpa...). The skimmer I use is a Big Mombassa, and it seems to do a 'just-okay' job. I'm not getting a full collection cup every week. Seems to be about ever two or three weeks that I have to dump it. Would a stronger powerhead improve this? Is there something else I've missed here? Where can all these nitrates be coming from? I feel like I'm missing a big part of the equation here. <I do not believe your test kit. Do you have/can you get another nitrate test kit? Having done all of this work (major water changes, removing gravel, etc.) and not see any difference makes me feel suspect of your kit. Do you have a good pH and alkalinity kit? pH and alkalinity should be depressed if you do indeed have this much nitrate and the corresponding dissolved organics. Please double check. As for your skimmer, try cleaning the powerhead and skimmer body very well and run the powerhead in a separate bucket with hot water and vinegar to remove deposits. This may improve your performance. -Steven Pro> Thanks, ~John

Re: High Nitrate Hey Bob, How are you? I think you'll like this one.  <Hmm, hope so.> Well I went to my LFS to get some macroalgae and live rock for my nitrate problem. I have been going to this store since I first set up my system. So I tell the owner about my nitrate problem and explained to him how my nitrate level have been weird, he suggested getting a new test kit, because something didn't sound right. So I got the rock and algae any way, just to be safe, when I tested my water the nitrates in my quarantine was less than 10ppm and in the display tank with all the live rock it was 0ppm. Is that unbelievable or what.  <What> So for the fun of it I tested the water using my old kit and sure enough the nitrates in both systems came up as over 80ppm. I still wanted to be sure so this morning I took a water sample of both systems to my LFS and had them test it and it was the same as what the new kit read. Needless to say I am happy.. Have a good weekend. Gillian <You as well my friend. Bob Fenner>

Re: Nitrates Thanks for this Anthony, actually, I own an aquarium store (large,350 tanks) here in Burlington, Ontario (before you gasp, I do not run it though), <heehee... too late. I sucked in a fly on that last gasp> down the road I do plan on bringing large specimens back to my store to put for sale, at there present size I do not believe the tank is overcrowded (the largest is a few inches), <agreed, my friend. Our advice here is proffered to serve the masses. In such cases where an experienced aquarist truly has the means to move such fish (and is not just dreaming of a big tank one day like most of us are..) then I am quite comfortable with it. I'll call my cousin Joey Bag-O-donuts and tell him to turn the car around. He's going to be disappointed but I feel confident that you are competent my friend and do not need a knock on the door from the Aqua Mafia> I have been using an aqua. Pharm. nitrate kit and in talking with one of my store managers think that the kit might not be any good though it is new, <very possible... I have had this experience verified> a 20ppm jump in a day is very high, and I just changed 20g last night and have a 20ppm drop, which to me seems like a hefty drop for a small change, what are your thoughts on these readings, <the sudden increase is doubtful but the drop from the water change is believable if only temporarily. If both prove to be true... then there is a flaw in the filtration dynamics> also should I be changing the "permanent floss" I have over the bio balls?, <not often... just rinse in aged aquarium water that is about to be discarded from a water change (no tap water)> I wonder of this being a nitrate producer, and your thoughts on the best "kit" or system for accurate nitrate readings, <no brand seems to have a full line of reliable kits without spending bug bucks for lab reagents (hundreds of dollars). I have always like Aquarium Systems test kits> thanks again, best site on the net, will be mentioning it to customers when at the store.....riotfishdude <I admire your faith in the educated consumer! It is the very thing that will keep us all in business. Kudos to you... what is the name of your store my friend? Anthony>

Nitrate Levels After Reverse Osmosis? Are there nitrates existing in r/o water ? If so how much? And, is there any way of ridding nitrates before putting r/o water in your tank?  <Nick, if your membrane in the R/O filter is good, your water should be 97/98% pure. I would do a nitrate test of your tap water and see what the nitrates are out of the tap, if any. I would concentrate on getting the R/O filter working properly rather than incur extra expense in removing nitrates from R/O water. Nick, in future queries please watch your caps and abbreviations. It does save the editor work as these queries have to be corrected before they can be placed in the FAQ's. Thanks in advance. James (Salty Dog)> <You're welcome>

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