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FAQs on Marine Water Quality involving The Actual Science of Nitrate Compounds

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: Importance, Measuring, 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 WaterChemical FiltrantsDeep Sand Beds

Nitrogen in a few formats is a necessary/essential make-up of foods, autotrophy. Antennarius commerson (Latreille 1804), the Giant or Commerson's Anglerfish.

NITRATES      2/1/16
Are nitrates just in the water column
<And in the substrate, solids>
or can they be absorbed by live rock and other things in the tank?
<Not the rock, but there are other... chemical filtrants>
I know phosphate can be absorbed into live rock. I am researching about nitrates in reef aquariums. Can you please
help me? Also is there any good reading on reef tank related nitrates and how to combat them other than what I'm seeing on the internet?
Jeff Greene
<A huge amount in the scientific literature; some sophisticated petfish books. On WWM Here: http://www.wetwebmedia.com/no3probfaqs.htm
and the linked files above. Bob Fenner>

The most difficult question. Coral hlth. issues; some poss. influences, corrections     12/13/13
Hello again Mr. F.
how are you? I hope all is fine with you .
I have a very important question: what is wrong with my system?
Let me explain: my 250 gallon display was set-up 1 year ago. 220 cm long, 70 cm wide and 70 cm high. Sump, AquaMedic aCone 3.0 skimmer rated to 3000 litres, biopellets reactor, antiphos reactor, active carbon reactor running 24h. Ozone , full line apex Neptune system computer with the following readings: ORP 350-390, pH 7.9-8.1 , temp 25.5-26.5 and salinity 34.5-35.0.
Calcium reactor, kH 7.2-8.0 , Ca 420-450, Mg 1280-1300.
History: maybe you remember all my inquiries about crypt and fish disease after my initial ordeal
<A good deal; yes>
With all my fishes dying in the first month because of crypt and Oodinium, I have spent hundreds of hours reading and learning. I now have Coral magazine subscription ( maybe one of the very few in Romania ) and dozens of books all read. About fishes , I now have all the fishes I restarted the system with, P. Hepatus, Chelmon rostratus, A. Japonicus, pair or mandarins, Z. Xanthurus, Naso  lituratus, P. Imperator ( juv. ) all 10 months now in the system and a beautiful Z. Cornutus six months now in the tank, all doing very good. So lesson learned there. ( I have 3. Quarantine tanks , I always perform fw dips with Methylene blue etc )
4-5 months ago I started introducing SPS corals. I always knew I wanted a SPS dominated tank with these beautiful fishes I already have ( only one P. Diacanthus is missing but I will get there also..) then the problems started. I discovered that I had high nitrates: about 20 on Salifert test so I started the maintenance program: got rid of the 2-3 cm sand in the DT because of the wrong depth, siphoning of the sump, changing the media in the reactors etc. I bought some more corals, some Acropora, some more Montiporas, Stylophora.. Because of a faulty salimeter ( the paper with the scale moved inside the glass )  the salinity went to 43  and lots of corals died or dying .
I slowly went back. After that, in September I drilled my pavement and installed a 300 l refugium with 18 cm sand bed and Chaetomorpha in the basement with reverse light schedule. After 3 weeks I installed another  200 l tank there with live rock. At the beginning I had some problems with keeping levels of water ( maybe you remember our discussions ) so the salinity varied 1-1.5 points daily for some weeks.
Before installing the calcium reactor I had some variations in the levels of kH and Ca. ,   1 month ago.
After that I thought everything was stable, so I introduced some more corals. But I kept losing some of them. Apparently  lots of Montiporas digitata died and also some Acroporas. In November, after the last addition on sand in the RDSB  and some more live rock the Cyano started. I had to leave for one week and when I come back more SPS were lost due to Cyano this time ( even thou my friend was at my house every day feeding and cleaning the Cyano).
<I'd throttle back your carbon additions. In fact, I'd remove the bio-pellets entirely. This/these are likely driving your Cyano problem here>
 So when I come back I reduced the lighting for the T5 ( I have an AquaMedic 3x250 w CoralVue ReefLux 14000 K plus 4 T5 x 80 w ATI 2 white 2 blue ) turning them off . ( they were on 12 hours ON ) . I only kept the MH. The Cyano receded , every day I clean it and blast with a 1200 l/h pump every rock and coral. But it continues to grow on some corals killing them.
I fragged some of the Acropora and the frags until now seem to be doing fine . But every day I discover that another SPS coral is declining.
Other values : nitrates : 2-3 Seachem test
Phosphates : <0.01 Salifert
<Not an issue; in fact, I'd feed more to increase>
Silicates : 0
  About the lights: after turning down the 4 T5 I have seen lost in coloration also in otherwise hardy corals : Montipora plates , so I have turned them on again and I have measured the PAR readings : bottom 150 -100 between bulbs, middle 230 and top 400. Under the bulbs 1100 micromoles/m2/second. . But before turning on again the T 5 (2 days ago ) the readings with only the MH were seriously lower ( 40-60 bottom between bulbs ).
In the meantime I have lost some Acropora that was with me for 10 months and survived all that. But there are some Montiporas and some a Acroporas frags that appear to be doing great so far. I have colonies of Stylophora and Porites that are ok.
So, why am I loosing  SPS corals? Is the stability of the system? All the changes I have done? Is there something wrong in the water even if I get all these " normal " readings?
<Toxicity from the Cyano likely is number one; perhaps a lack of chemical food (too little soluble phosphate) is an issue as well>
It gets pretty frustrating because is not only the money ( by the way water movement is done by 4 Vortech MP 40 ) but all the energy and study time ( we have 2 kids 2 and 5 years old so time is important)
<It always is my friend. An important "lesson" in life is to learn how to portion ones attention. "First things first"... your own health, happiness; the family and friends about you... petfish are way down the line of importance>
 and the willingness that I feel I am starting to question.  I feed the fish 4 times a day ( defrost and rinsed Mysis and krill and bloodworms, spectrum pellets, Nori and Spirulina and 2 big fresh clams ( I think this is the term, the black shells) that I keep in my hands until everything is eaten. All the fish eat a lot and they are fat. But I arrived in one point when I look away from the DT when I pass by, just to avoid seeing sick corals . It was not easy at all, all my friends consider me strange at least do all this for a reef tank, even if they like it when they come by. Keep in mind that I live in eastern Europe where LFS are far away and don't stock livestock, and for example a A. Japonicus costs 250 $. For me, having a SPS tank would mean that all that I have done is worth it, but something is wrong, and I am not sure what it is. My wife is supportive, but I would really want to see some results .
So in conclusion I feel that I have done a lot of efforts and at the moment I cannot see the results, so it seems it is very difficult, but I see a lot of successful tanks done with maybe less efforts and I am wondering what am I missing.
Thank you for your patience,
Andrei in snow covered Romania
<BobF in (today) sunny S. California. Do remove the carbon additions and increase the feedings>
Re: The most difficult question. More Biology, Less "Technology""      12/14/13

Hello Mr. F
<Mr. Andrei>
thank you for your answer.  I will stop the biopellets reactor, I was just not sure if my RDSB is mature enough to handle the denitrification by himself,
<You'll likely see no change in NO3>
 my plan was that when the nitrates would arrive to zero I would stop the biopellets .
About the nitrates, increasing the feeding sounds great, but aren't they the ones that fuel the Cyano?
<Not necessarily, no... see WWM re the several inputs here>
 Shouldn't the desired levels be zero absolutely?
The chemo-autotrophic life (e.g. corals, many microbes, algae... ) NEED some/measurable nutrients, including nitrogen compounds and phosphate>
Because I also have a anti phosphates reactor running as well... If the chemical food might be missing for the corals,
maybe I should feed more amino acids and vitamins ( I do it like once every 10 days half the dosage ).
<Am not a fan of such reactors in most settings... "More Biology, Less "Technology"" Is my motto here. B>
Thank you again,
Re: The most difficult question; further input re a/the mysteries of too much, too little and out of balance nutrient issues      12/14/15

Thank you. The biopellets are off.. will see what happens. I took the biological route for sure, with the refugium and live rock tank.
What about all the beautiful tanks in several ' tank of the month ' editions that report zero NO3 and PO4 ? Normally you don't see any outstanding SPS tank presented that has any detectable nutrients.
<Mmm, allow me to "try" explaining: All systems have something/s that are "rate limiting"... An example, let's think of you and I and our desire for more "stuff"... We're likely limited by funds/money... Most aquarium systems have a nutrient limitation... but it is not often well-understood what this is (a topic of huge possibilities): Your system is likely being "too driven" by an excess of available carbon... which is fueling the BGA/Cyano, that in turn is poisoning your stony corals... I am hoping by limiting the carbon and allowing sufficient simple nutrient presence, to have your Scleractinians (et al.) outcompete the Cyano. Now; as to those other systems that are in "apparent balance"; they have NO3 and HPO4 limitation... BY the desired organisms taking these up readily; NOT by their reactor/media removal>
I think this is very important. Lots of people out there would benefit from understanding these basic philosophies.
<Ah yes; I do so agree. Do you understand me above here?>
Please consider that I want nothing less than the most beautiful SPS tank with colors and corals health. I am willing to invest time, energy, and money. What would you recommend as optimal values for NO3 and PO4?
<Low, but still measurable.... a few ppm for [NO3], and 0.05-0.01 ppm or so for [HPO4]>
  And after my system description do you think I would need anything else as hardware or technique?
<Mmm... likely THE best investment in your study, gear is an understanding of RedOx potential, perhaps an investigation into ozone... >

Thank you,
<Thank you Andrei. BobF>
Re: The most difficult question     12/14/15

Oh, and this reading: http://www.wetwebmedia.com/ca/volume_5/volume_5_3/phosphates.htm
Re: The most difficult question     12/14/15

Tank you, I understand.
One more question: I run ozone on my skimmer and have a 350 -380 ORP reading. What do you think about these values?
<I see... this is very good. B>

Bacterial Bloom or Algae?     8/14/15
I've had three outbreaks of something in my tank and no one locally seems to know what it is exactly.  It basically looks like white snot all over the tank.  Clears up for about a week comes back brownish. Clears up and returns as white snot again. 
I was told it might be dinoflaginate.

My stats are as follows:
30 gallon innovative marine tank AIO
Amm 0
Nit 0
Nitrates 0
PO 0
<.... autotrophs, your "corals" and more need measurable NO3 and HPO4>

PH 8.4
Cal 430
Alk 10.2
Salinity 1.025
Using a innovative marine skimmer
Activated charcoal
<I'd skip (take this out) for a while at least>

Starting dosing MicroBacter7 10 days ago based on someone's suggestion. 
Not much of a change.
Any help greatly appreciated. Thanks.
<Mmm, I'd also not change out the activated carbon for a few weeks... you may have inadvertently triggered a bloom of some sort (need sampling and microscopic examination to know what)... Do read on WWM re NO3 and HPO4...
Bob Fenner>

full size...
Re: Bacterial Bloom or Algae?    8/14/13
Thanks for the quick reply!
Earmuff Wrasse
Christmas Wrasse
Maroon Clown (2)
Diamond Watchman Goby
Green Clown Goby
Hi-Fin Goby
Surf N Turf Acro
Tri-Color Acro
Strawberry Shortcake Acro
Rainbow Millepora
Candlelight Acro
Green Pollicpora
Montipora Digitata (3)
Montipora Capri
Brain (1)
BowerBinki (1)
Various Zoas/Palys (8)
Pistol Shrimp
40lbs live sand
40lbs live rock
Normal Maint:
5 gallon water change every week
1/2 brine cube per day
<.... I'd expand this... very likely use a pellet
(Spectrum, Hikari) as my staple... frozen/defrosted in the AMs... PE Mysis, blends... Not Artemia regularly; for reasons gone over and over on WWM; including the issue/s you're having here>
EcoTech Radion Pro at 53% intensity of a 20K spectrum
Tank has been running for 6months.
I've started 5 gallon water changes daily and plan to continue for the rest of the week, do I need to do more?
<More? As in more volume? Not likely; unless something dire in the shortish term is of concern>
I'm using Hanna Instruments to check for PO4 and API to test for NO3, do I need to use different tests to measure?
Should I continue to use the MicroBacter7 daily?
<I wouldn't. Of no use here; in established systems>

I did just change the carbon but it was after the bloom.
<No need for the extra C, as in the element>
How/where can you get a microscopic examination?
<Search WWM re; you may well enjoy and definitely benefit from having a 200-400X 'scope... BobF>
Re: Bacterial Bloom or Algae?
Hopefully the video isn't too large, it shows the problem better than photos.
<<RMF Linked here: WWM Video/Video Clips/Video Ter.MOV
Video Ter.MOV
<See some "waving slime" off your stony corals et al.... Could be... reaction series... as noted; from deficiency syndrome/s; perhaps allelopathy, though I discount this... in such a small volume, you would highly likely see/have REAL troubles if so; fish dying etc... You really need a much larger (volume) system... for the stock shown, your obvious ambition/s; dilution... B>
Re: Bacterial Bloom or Algae?    8/15/13

I just want to make sure i got everything correct:
Continue daily 5 gallon water changes for 2-3 more days then resume my normal once a week 5 gallon water change.
Feed spectrum marine life 1mm pellets as primary food and supplement a couple days with brine.
Either reduce the number of fish/corals or get a bigger tank.
Remove the RowaPhos for now.
Purchase a 200X-400X microscope.
When you say measurable NO and PO, what's my target reading?
<... DO read on WWM re: 5-10 ppm of nitrate and 0.01-0.1 of phosphate is about right. Don't "lose your mind" re periodic values higher/lower>
 What's the acceptable range?  I was always told zero.
NOT zero; none detectable, no food/life...>
Thanks again!
<Certainly welcome. BobF>

Maintaining a favorable level of nitrates and phosphates    8/9/11
Greetings again, Crew. I'm writing to you (again) with some questions over some information I've gleaned from your site over the last few days.
In particular, upon reading Bob Fenner's article on stony coral feeding posted to your site in February of last year, it has become abundantly clear that the "aggressive protein skimming" that magazines and LFS's endorse as the industry standard may, in fact, be robbing our system of DOC's completely in removing the still organic debris in our systems. I am currently seeking a way to allow an acceptable level of Nitrates and Phosphates to enter into my system, in order to promote better health/growth/color for my Cnidarians.
I have a Biocube 29, running a CPR SR3 skimmer which, in this lidded system, is the main method that I'm adding oxygen to the water (so I've been told, this is a great benefit of skimming).
<This is so>
I also run a bag of Chemi-Pure Elite, and a bag of Purigen. This is a direct result of trying to starve out a diatom and Cyano bloom that occurred in two separate instances. It was suggested to me prior to allow the chemical media to age, and not replace too frequently.
<Yes; a good idea/practice>
Would it be acceptable in a system of this size to only run one bag of chemical media?
Also, Mr. Fenner's article suggested running punctuated skimming (particularly to shut off the skimmer during feeding for a short while).
What is a recommended period for skimming, and will this have a large impact on the oxygen levels in my system?
<As long as the system is "not too crowded, overfed..." you should be fine to run the skimmer on/off every few hours; particularly off during nighttimes...>
(Unfortunately, testing for dissolved oxygen is still out of my reach at this point.) I am hoping that with a few minor tweaks I will be able to afford my underwater acquaintances with a more suitable environment.
On an unrelated note, I am eager to give back to the community in the only way I know how: observation and documentation. To do this, I have set up a personal page on a website that allows me to post pictures of my tank and write up my observations.
Would it be permissible for me to occasionally post links to articles on WWM?
I have learned so much through your helpful articles, and would like to be able to point others in the direction of your expert advice and care (while of course maintaining that I am in no way affiliated with those who operate WWM).
<Ahh, I hope in time you may join us, as a Crewmember, mentor... dive/adventure co-traveler>
Thank you for all you do!
<Welcome. Bob Fenner>

Re: Maintaining a favorable level of nitrates and phosphates   8/10/11

Many thanks to Bob for his through and encouraging response. And hello to all on call today!
<Hey back Dustin>
Very quick question this morning: what are the optimal Nitrate and Phosphate levels, as the "zero across the board" approach is proving less and less affective in home aquaria?
<Really, any appreciable... measurable... Higher than 0.0, for hobbyist settings>
Thanks again!
<Welcome. BobF>

Brownian Motion not yet Resolved with General Relativity - Flow of Nitrates to DSB Dear Crew, <Paul> In a new tank, I am building an oolitic deep sand bed (DSB) for natural nitrate reduction (NNR). Without a plenum, how do the nitrates reach the lower layers of the DSB where they can be consumed by anoxic and anaerobic organisms? <Brownian motion/kinetic energy, molecular density/gravity. Bob Fenner> 

Nitrates in a large Tank Hi, I need some expert advice on nitrates, if you don't mind of course.  I am in the process of planning a filtration system for a 3200 gallon fish only system. I will be using 68 square feet of bioballs, a turnover rate between 8-10 times of total water volume, micron filters, U.V sterilizers and two large skimmers.  One aspect I not sure about is the nitrates.  This would be a community fish tank and to do water changes to keep nitrates in check might seem impractical,  I don't know not sure.  How do the fish stores do it? do they have some type of system that removes nitrates?   If you can offer some advice I'd greatly appreciate it. Thank you and have a nice day, Joseph Ditommaso <Large systems like this, particularly ones with so much nitrification (68 cubic feet's worth), can be nitrate controlled best by the use of equivalent amounts of denitrification surface area (live rock, DSBs) and/or consumptive matter (e.g. macroalgae grown in place or intensely in refugia). Bob Fenner>

Ich and Other Questions (6/17/04) Thank you for the response below <you are welcome> but I have a few more questions: 1. I am treating the quarantine tank with copper to cure the ich on the cowfish. He's been in there almost two weeks and the scooter dragon shows no signs of ich. I'm willing to be patient but how long do you think I should leave it before reintroducing the cowfish? <I'd keep the cowfish out for a total of eight weeks to maximize the odds that the ich will not return when he is re-introduced. I know that my fellow crewmates don't generally recommend UV sterilizers, but you might want to read what Scott Michael had to say about them in the 2004 edition of Aquarium Fish USA, which you should be able to find at Petco or PetSmart. I used one as a supplement to help rid my tank of ich, and I am convinced that it helped.> 2. On a separate issue, I've read several times on your website that filters such as BioWheels make too much nitrates and overwhelms the anaerobic bacteria, so using live rock as filtration is a better approach (I've got a BioWheel btw). I must be missing something - isn't nitrate created by bacteria from nitrites which come from ammonia, and since ammonia comes from waste in the tank isn't the amount of nitrate production only dependent on things like stocking and feeding levels? In other words, how could a BioWheel make more nitrate than live rock with the same level of nitrite and ammonia? <Good question. The problem stems from the fact that the Bio-Wheel (or Bio-Balls, etc) does not take things to the next step, which is the anaerobic conversion of nitrate to nitrogen gas that then exits the system. If you have enough deep sand and live rock, the nitrates from the Bio-Wheel should get processed there, but if you have that much LS & LR, you don't need the Bio-Wheel. I should like to point out that the whole concept of LR as a filter has been called into question. Read here: http://reefkeeping.com/issues/2004-05/rs/feature/index.htm The nitrates are really only an issue in tanks with inverts. Many still recommend Bio-Balls or Bio-Wheels in high-nutrient load FOWLR predator tanks. Of course, nitrates can reach levels harmful to fishes too, so routine water changes are essential in this scenario.> 3. If I was going to switch from the BioWheel to live rock how would I do it? Do I need to do it slowly to enable the aerobic and anaerobic bacteria to build up? Do I need to use a DSB in conjunction with live  rock? <Not necessarily, but very helpful. One would proceed to slowly add enough rock until the Bio-Wheel can be safely removed. Much info on this already posted on WWM, mostly with regards to Bio-Balls. Search the FAQs. Also, consider buying a copy of Bob & Anthony's "Reef Invertebrates" There is 100 pages on LR, DSB, refugiums, algae. An excellent resource.> 4. Finally, apart from the looks aspect, if growing macro algae is a good thing because it uses up nutrients why isn't it ok to let micro algae grow? As in, if I let my tank go fallow because of ich what is the harm in letting algae grow on the glass if I still do other maintenance? <None really. Some algae can have toxic effects (like crashing Caulerpa), but hair algae is not harmful, unless it grows to such excess that it crowds out other desirables such as coralline algae, and corals of other sessile invertebrates. The big problem is that if you let it go too long, it will be hard to get it back under control.> Thanks, Matt <Hope this helps, Steve Allen.>

- Questions about Water - <Greetings, JasonC here...> I started my water cycle about 9 weeks ago the first 4 weeks I add salt to the water, and then I put like 10 damsels for 5 weeks. 1st question is, a few days ago when I went to the fish shop, and I bought a clown trigger and a puffer, but I took a water sample from my tank and the guy from the store told me that the nitrate was very low, so I sold me a bottle I think is called "NitroMax" that are like two bottles attach, I think one of them is oxygen and the other one is bacteria I said to add like one teaspoon for every ten gallons (which I did). Today I took another sample of water to another store (octopus's garden), and they told me the nitrate was very high??????? so my question is if its low there's not enough bacteria, and if its high its dangerous to the fishes???? <Low nitrates aren't an indicator of a lack of bacteria... this is a very new system, I wouldn't expect a high nitrate reading in a tank of this type.> every body is giving me different opinions???? <I don't see it quite that way... I think perhaps you are misinterpreting the data. The tank is new... nitrates build up slowly. The NitroMax was not necessary, but by adding this and the new fish you increased the bioload which would also increase the amount of nitrates - none of these things are a surprise.> so I guess the more convenient thing to do is buy the NO2 Profi Test Nitrate Kid, and the PH Profi test kid and hope You might give me the correct advice....... <My friend, you should do some reading and learn to trust your own instincts rather than be swayed by other's advice.> what they last told me is that the nitrate test should appear white  0.00% of the purple color chart, and that the PH should be in the 8.3% that is the green color on the color chart. <In the ideal world... there is a range to these things and also a little give and take. For pH, a reading between 8.2 and 8.4 is ideal - 8.5 or 8.1 is not a disaster. Likewise, depending on the type of system you 'want' to have, a reading of zero nitrates may not be practical, and even 10 ppm would be just fine. Give these things time... this is a very new tank.> PLEASE advice me which is the correct information?????? <Actually, I will plead with you, read this link and inform yourself: http://www.wetwebmedia.com/marine/setup/filtration/biological/biofiltr.htm > My second question is I already both the Marine buffer "SeaChem" brand to maintain the correct PH since it was like 7.9,  and the Nitrate was 4 that they told me it was extremely high should I do a water change or there's some chemical that can lower it down if needed  (please tell me which of the information I received its correct the one that the bacteria is low, r the one that the bacteria and PH is high)... <All the information you have gotten so far is subjective - it all depends on the information you give the people who are giving you the advice. If I were you I would relax, breathe deeply, and let the tank do it's own thing. Don't be so hasty to add any/everything that come in a bottle.>  I really appreciate all of your help and information. 3rd question I herd that in the la Jolla aquarium they give you perfect salt water for free, is it better to go and get these water or is the same if you make it correctly with purified water (bottle water) adding the salt correctly????? <Well... it is true that there is a filtered seawater spigot at the Scripps pier, and this is the same water they use in the aquarium. BUT... unless you are prepared to let this water sit for as long as a week, and then filter it before you add it to your tank, I wouldn't recommend it. In fact, at this stage in the game for you, I wouldn't recommend it at all - this same water has been responsible for wiping out entire tanks to those who didn't handle the water correctly. Stick to mixing the store bought salts. In the meanwhile, please read this link and better inform yourself about using seawater: http://www.wetwebmedia.com/seawater.htm You might also want to consider joining our local marine aquarium society where you can meet other people with similar interests: http://www.sdmas.org/ > thank you for replying. <Cheers, J -- >

Nitrate Reduction... Hey Crew, <Scott F on call today> I think I have finally got my head around the nitrogen cycle involved in an aquarium.  I was hoping that you could confirm it and also give me some helpful hints.  I will use my tanks filtration setup as an example.  I have a tank with a built in trickle filter at the top. The first section just contains prefilter wool. <Don't forget to replace the prefilter material regularly and often...If neglected, it can become a nutrient "trap" that will degrade water quality> The water then runs under a small baffle into a section filled with Seachem Matrix (last time I wrote to you I asked you about this Matrix and you informed me that it had to be replaced. I have since found that this is only the case with Matrix carbon, which is a relief as I can't really afford that on top of everything else at the moment).  The Matrix surface when matured contains aerobic bacteria which breaks down ammonia into nitrite and nitrite into nitrate.  It also contains anaerobic bacteria in the porous area found inside the matrix.  This bacteria breaks nitrate down into nitrogen by extracting the oxygen out of the nitrate (hence if the 3 parts of oxygen are extracted from NO3, nitrate, then you are left with N, nitrogen gas that is simply gassed off at the surface).  Is this correct,  or am I a bit of track?   <You pretty much got it, dude> Also, I want to lower my nitrate level, would the introduction of more live rock help since it contains anaerobic bacteria. <Live rock certainly functions as a natural biological filter, but I would not rely solely on the rock to remove excess nitrate. And- utilize small (like 5%) water changes twice weekly with high-quality source water...this will discourage organic accumulation before it becomes a problem> Also would live sand help? How thick should the layer be?  Thanks in advance. Amon <Well, Amon- I think that a properly constructed "deep sand bed" (one that is 4 to 6 inches deep) will provide very significant nitrate reduction, and the nitrifying bacteria residing in the sand bed will also help compete with algae for the available nutrients! Be sure that you are using a fine grade of "oolithic" aragonite, such as CaribSea's "Aragamax Sugar-Sized" sand. The fine sand will also dissolve over time, providing some degree of natural pH maintenance and buffering. Read all about sand beds on the WetWebMedia.Com site, as well as Bob Goemans' saltcorner.com site. Good luck! Regards, Scott F>

Nitrates I wrote before and was not specific enough in my email. Sorry. <No problem Abby, let's see if we can get it right this time!> I have a 110 gallon tank that is 10-months old. I have a flame angel, blue tang, 2 damsels, 2 neon gobies, 2 sally light foot crabs, 2 cleaning shrimp, 8 turbo snail and 100 pounds of live rock. I also have an open brain coral, a colony coral, and a finger leather coral. I started the tank using the Tidepool BioWheel by Marineland. I did do readings ahead of time and knew a little about wet/dry trickles becoming nitrate factories but it was the best option for me at the time. I have read that you have suggested to others to remove a little biomedia at a time. This will not work in this case because all the media is contained together in a wheel. Right now, nitrates are at 10 ppm with ammonia and nitrites at 0. I was wondering what I could do to avoid the onset of serious nitrate problems. I change 20-30% of the water weekly, utilize a Fluval 404 and Berlin protein skimmer as well. Is there any media I can replace the wheel with and then remove that slowly or should I remove the wheel completely. thanks for your help. Abby Kengersky <Alright, you want to wean your system from the BioWheel and fully loaded Fluval. The amount of rock you have should be able to handle the bioload you have. Not too many fish at all for 110 (congratulations!). If you feed lightly it will help make the transition easier but your LR should be able to handle the fish you list. I would also think about the Fluval being a similar problem. Most folks I know use them for carbon periodically and run them empty the rest of the time. It sounds like it is just the nitrates produced by the filters that are the problem so make the switch, test and be ready to change your water (sounds like you already do). You might consider adding more well cured rock or a deep sand bed to help with the nitrates. If you are worried about a fallback position, keep the BioWheel filter running in some heated change out water just in case you need it. Not to worry, my bet is the BioWheel and Fluval produce the nitrates. Just give the rock (your real biofilter) time to adapt if needed. Make sure your circulation is adequate. (Up to 10X volume for reefs). Craig>

Re: question I can not get over how quickly you reply.. <I key quickly> Ph is 8.2 Nitrate is 160 ppm if not higher <Yikes! This IS high... wonder why?> Ammonia is 0ppm NO2 is .25 ppm <Hmm, and this should be zero> In the instruction manual it says maintaining a low nitrate level improves the health of fish and invertebrates.. A high nitrate level indicates a build-up of fish waste and organic compounds resulting in poor water quality and contributing to the likelihood of fish disease. <As a general "rule" this is correct... but many approaches to keeping marines greatly add to nitrate accumulation... i.e. wet-dry filter media, fluidized bed filters, a dearth of substrate, not enough or any live rock, a lack of livestock that take-up this nutrient... like macro-algae> So that is why I thought there was a menace in the high nitrate. I also thought that because I read most of the faq's on WWM I thought asking you would be the beginning to starting a good foundation. I'm trying to learn form a reputable source. <I understand... but, can you imagine learning any subject area in this way? Let's say arithmetic math... Instead of learning "tables" and "math theory" to simply ask "what is... 4 plus 5?" and so on and commit this to memory... instead of having a grasp or principles and relevant examples? I want to insure you are successful by having a thorough enough understanding of underlying cause/effect> Also I noticed the endings in your help to others you say my friend. You don't end mine that way. Should I be concerned? Thank you Jenn <No my friend... as I term folks who "turn me on to the good they've found in their lives and away from the bad"... Just my rude hastiness in responding. Forgive me> Here's a layout of my tank if it matters 125 gallon 2 sea urchins, 2 lionfish,3 yellow tangs, 1 nasal tang, 1 Picasso trigger,1 blue jaw trigger,2 blowfish, 1 toadfish, 1 golden spotted eel and a nurse shark <Wowzah! This is a lot of life in a hundred and twenty gallons... do hope you have plans for a MUCH bigger system... and soon! These fishes will produce enough nitrate for the biggest of aquarium filtration gear. Be chatting. Bob Fenner>

Experimenting Bob, I have a 240 fish only system with 100 so lbs of live rock, 2.5 in. of aragonite "nonliving" substrate. Below wet dry system with bio balls. Turboflotor skimmer inj. 50mgh ozone , and UV sterilizer. The tank has excellent circulation the return pump that Am using is a MAK4. Which creates awesome water movement. Here I'll list the fish for you please look carefully, as I would also like your opinion regarding my livestock load. 1- 9" Vlamingi Tang 1- 9 " panther grouper 1- 7 " Miniatus grouper 1- 3" Atlantic blue tang 1- 6 " Naso Tang 1- 2" common cleaner wrasse 1 4" Huma trigger 15-20 ass. hermit crabs for clean up crew <Looks like a nice grouping for a 240> Here's my current water parameters ammonia=0 nitrites=0 nitrates = 25-45 ppm PH = 8.0 Ok finally here's my main question. Last night before I did a water change I tested the nitrates. My nitrates are always at between 28ppm- 38ppm. Always around that ball park. On my calendar it was time to do a water change. I usually do a 20 gallon water change every 12 days. Last night I decided to do a 40 gallon change. This morning when I got up . I did a water test on nitrates. How come my nitrates didn't budge AT ALL ? They were at the same , about 35 so ppm. <Your system is "getting old"... the nitrifiers on your bio-balls more "efficient"... the denitrifiers losing "space" as your substrate "melts", becomes more "rounded", smooth... The balance of the nitrification/denitrification equation is shifting to the left... you can nudge it back the other way by adding/replacing substrate, placing more rock, ditching your plastic biomedia, adding a sump, macroalgae, refugium, mud filter...> The water change that I did last night was pretty massive. Also I never over feed my fish. I Feed them small portions once a day, making sure that the food is being eaten up right away. My groupers eat only about 3 times out of the week, little each time. I remember you told me before that 28 ppm of nitrates was no problem for a fish only system. Then how about 38 ppm?? <Getting up there> My fish look great. Excellent color, behavior feeding etc.. Should I let my fish give me the signal if my water is good enough?? Can you give me a specific range?? <Under twenty is about right for a FOWLR system...> PS I plan on getting a Emperor angel, that will be my next fish. Are my nitrates ok for large marine angels??? <I would wait till this is lower... Bob Fenner> Sincerely, Linstun Lee

Re: experimenting Bob, My 240 system is only been up and running for 2 months. Officially its only 2 months old. What could be the problem with the nitrates?? <What do you mean, "trouble"? Why are nitrates accumulating in your system? More nitrification than use (like by photosynthetic life) plus denitrification... minus dilution by water change... minus precipitation... minus extraction by skimming... A few more factors can/could be written into a linear equation... Simple categories of input/output.> I use RO water , and vacuum up the substrate good each time I do a water change. Thanks <Study my friend... calm yourself. You will know. Bob Fenner>

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>

Nitrates in a marine tank We have had a marine tank for 10 going on 11 weeks now and our water test has shown that our nitrites in our are too high.  <Nitrites with two "I's? Not good. In the subject heading above you call the compound: Nitrates with an "a"... I'll assume your concern is with the accumulation of nitrification products. Please read the FAQs here: http://www.wetwebmedia.com/no3probfaqs.htm there are a few standard ways to reduce the nitrate concentration in captive marine systems. You don't mention specific concentration... I assure you that NO3 by itself is not a dire problem.> We have done a water change and a gravel clean but our levels are just not decreasing . What would you recommend? <Please read through the "Marine Set-Up" and "Maintenance" sections posted on WetWebMedia.com for background on the myriad of methods, causes that could be at play here... You will find that adding more live rock, substrate, photosynthetic life is a routine way to combat increasing nitrate, as is removing its source in mis and overfeeding, use of nitrification driving media (like those in wet-dries, fluidized bed filters), improvements in filtration (like skimmers)... Bob Fenner> Yours sincerely Lémay & Andrew Thanx!

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 Perculas 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 Mombasa, 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: Anemone & Nitrates in a saltwater tank Bob,  I read your reply regarding the nitrates in my aquarium - I haven't done anything yet because I have multiple questions and because I have to order the anaerobic media that you suggested, it appears that the stores here do not carry any. <I understand> Anyway, to start with my questioning  1. I thought that the reason for the bio wheel in the tidepool was to create the same anaerobic media that the other stuff was for. This was just supposed to be a simpler way of doing it. What is the purpose of the bio wheel? When we do take out the bio wheel and add the other material - how do you suggest that we do this? Where do we put the other material, in the bottom of the sump where the bio wheel was or in one of the trays that the water flows thru? Do we put it in a bag or leave it loose. Do we do it all at once or gradually? <The BioWheels (tm) and other aerated (water and air mixing) devices of aquarium use are nitrifying mechanisms... a "forward" reaction if you will... promoting aerobic (oxygen using) microbes to change ammonia to nitrites to nitrates... The "opposite"  reaction direction denitrification only occurs expediently in low to no (anaerobic) conditions... Hence the use of plenums, thick sand beds, live rock (with lots of little nooks and crannies), anaerobic filter media... The BioWheel is intended to drive nitrification... which is does exceedingly well... too well in your case. Making excess nitrates and all the bad things that come with them... excessive algae growth, complexing of other chemical reaction pathways... The wheel can be removed... or water path redirected to exclude it. The anaerobic filter media can be placed in the trays, and or bottom of the sump... without bags... all at once or as you acquire it... > 2. You suggested that we add more live rock - we currently have approx. 60 pounds of Fiji rock in a 75 gallon tank - how much more would you recommend? <Up to a pound and a half of "average" size, density Fiji rock is about right, optimum> 3. You stated that we need to get a bigger skimmer - the skimmer that we have runs on the same purpose of the CPR Cyclone Bio filter only on a much larger scale, it stands approx 24" tall and has two chambers, one being the bio filtration. It also has a 2100 Rio pump. Is it possible that this might also be part of our nitrate problem? <Possibly, or that it just needs cleaning... About once a month, do turn the unit off, scrub and rinse (freshwater) the contact chamber and collector cup... Also, please look into the possibility of upgrading your Rio with the later generation "needle wheel" impeller...> 4. I also read in your web site that a peppermint shrimp will help take care of the glass anemones, will they bother any of the other anemone's or polyps?  <Not initially, or preferentially... Lysmata wurdemanni almost always first consume Aiptasia... but one needs to be diligent, and remove them at some point of balance or be careful in terms of stocking density... should not be difficult in such a large system...One or two for you> Will the peppermint shrimp get along with the Skunk Cleaner shrimp or the Fire Shrimp (current residences in the tank). Since it appears that every shrimp goes by a different name, Is the Peppermint shrimp the small one that is like a dark brick red with little tiny lines on it - not nearly as showy as the other two shrimps?  <Yes, and yes... will post the two animals sold as the Peppermint Shrimp... and my pix of these in better resolution is part of an article in the hobby magazine FAMA's April issue> P.S. What exactly does a glass anemone look like anyway - the one that I have in my tank that I am suspicious of is almost invisible in the rock because its color blends in with the purple - his tentacles appear to have bubbles or stripes in them (magnifying glass) He is still very small, maybe 1/3 to 1/2 inch. He also appears to look like several anemones that I saw in another pet store that they said was a striped anemone, keep in mind that this pet store does not have a good reputation for honesty. The anemones that they had were considerably larger 2" or so. <There are a few species of Aiptasia, and some other "pest" anemone groups... Again my images are in FAMA and Home Page ... Most have narrow columns with light brown-clear, narrow, pointed tentacles> 5. You also mentioned that we should increase the intensity of our lights - currently we have two 36" fluorescent lamps - 1 Interpet Triton and 1 Coralife Actinic 03. We have an acrylic tank with a wood canopy over the top, what would you suggest we use to increase the lighting - would another double strip work?  <Yes... if it was my 75 gallon tank though, I would seriously look into compact fluorescents... You need much more light than four 30 watt lamps will supply> I really appreciate your help, it's nice to get other ideas as we really only have 1 aquarium store here that is even worth looking at. I have spent a lot of time on your web site reviewing your notes and find it very informative, hence more questions. <Glad to be here and help you with your self-discovery and learning> Thank you again for your help, I am sure I will have more questions for you later. Annette >> <Looking forward to it, Bob Fenner>

High Nitrates Bob, First of all, thanks for maintaining such a great site and being such a great source of information for all of us. You've answered one or two of my questions before, and I appreciate it. <You're welcome> Now, to the tank: I have a 55 gallon fish only tank, onto which I've recently added a 18 gallon sump, for the purposes of hiding all my filtration from view. <And more I surmise> Currently, my filtration consists of ~30 lbs of base rock (formerly live rock brought out of storage) and ~5 lbs of cured rock (another recent addition), a 3" live sand bed with a 1.25" plenum, a CPR Bak Pak 2 Skimmer, two Fluval canister filters running as permanent biological filtration (bio balls, ceramic media), an 8 watt UV sterilizer, a Bio Wheel Pro 300, a lifeguard fluidized bed filter and a submerged internal filter running carbon and phosphate remover media. I've recently added several large specimens of Caulerpa to the main tank, and they seem to be doing well. I've also recently begun using PolyFilter to remove a large amount of copper that I had previously used to treat ick, and while I haven't tested my copper levels since, the pads no longer come up blue. I also haven't tested my phosphate in a while, but I have some confidence that the levels are low due to the lack of algae growth and the recent introduction of the phosphate absorbing materials. My test parameters follow: pH: 8.3 specific gravity: 1.021 ammonia: 0 nitrite: 0 nitrate: 120+ ppm!! In reading through your site I see you have little positive to say about either fluidized bed filters or bio wheels, calling them "nitrate factories" and saying that they overdrive the nitrification process.  <Yes, well-stated> My question (besides the obvious reduction of nitrates) is this: how can these filters overdrive the nitrification process if they don't have ammonia and nitrite to process?  <Hmm, well, no... but they "get", "scrounge", "scavenge" sources of these essential materials from many sources... besides the starting points of "wastes" of fishes, non-vertebrates... such as peptides from foods directly...> Aren't these the only sources/precursors of nitrate in the home aquarium? It would seem to me that one couldn't overdrive the process, as it only happens as fast as ammonia and nitrite are created. Is there something I am missing?  <Perhaps... it may well be that you're accustomed to thinking linearly about these matters... e.g. A leads to B than to C... the living and non-living world is much more complex... with ammonia coming largely through catabolic processes from the "breaking down" of peptides... but not always via microbial shunting of ammonia then nitrite then nitrate... with the microbes waiting to do their bit... they may well be skipping some steps, shortcutting in your cycles...> I would agree that my test results show that nitrification is occurring much faster than denitrification, but is the answer really to slow down to forward direction of the reaction? <Hmm, not necessarily... you/we can speed up denitrification as in adding more hypoxic substrate (like live rock, plenum, deep sand space...)utilize biological agents to "use up" available nitrate (like the Caulerpa you've added), slow down the "forward reaction" of nitrification by limiting inputs of nitrogenous foodstuffs, using ones that are more nutritious, palatable, feeding in ways that they make their way more into the intended livestock... Adding, encouraging predators (other microbes, Protozoans, even types of algae that consume, displace nitrifiers... Even pull their homes or circumstances (wet-dry media, spray bars/drip plates...> Please help me understand.  <I think you do, will now.> Finally, after several water changes, the nitrates still remain at this toxic level (I guess the fish are acclimated at this point), so should I add some nitrate sponge for temporary relief? <These levels are not likely (very) toxic... I would not lose sleep, or use chemical filtrants. Clean your skimmer cup and contact chamber... maybe upgrade it, add an ozonizer, maybe a desiccator for the ozonizer... Definitely consider adding more live rock, better lighting, possibly some lighting and rock plus Caulerpa in your sump... Cut back on feeding (especially proteinaceous foods), and try not to over worry. You're obviously sharp and determined for your livestock's welfare... and all will work out> Thanks for all your help, Josh <Again, you're welcome. Bob Fenner>

Not a query ... more of a discussion Hi Bob, No query this time .......... just thought you might be interested in a little mini project. It concerns no3 accumulation, and how water changes effect it. For example, what effect will doing two 20 gal changes have compared to doing 4 10 gal changes and so. I know the "little and often" premise, but the question is "how little" and so on. <Interesting, intriguing and very useful experiments/information> So, I have wrote a spread sheet using MS excel 97, which allows the user to enter 1) Initial no3 level, (2) the amount of no3 which tends to accumulate in one week, (3) the sizes of water changes performed, and (4) How often i.e. one ever 2 weeks etc. <Okay> It will then estimate the level after any amount of water changes ............ say for example you knew that after one week your NO3 level would rise from 20 ppm to 25ppm .........a rise of 5ppm, and say you had records which show this to be a typical value over a period of time. Now say that you read your level, and you find that the water changes you are doing are not adequate to keep the level below say 20 ppm. Well, if you enter your details into the sheet, it will allow to you estimate how many changes of what size to reduce you system no3 level to the desired range. You could then enter your desired range as an initial value, and see what water changes are necessary to keep it at this level. This was all brought on by recent discussion with fellow aquarists over the net, and an article on the link below http://www.animalnetwork.com/fish2/aqfm/1999/jan/bio/default.asp No need to click onto this site, it just here for reference. But, the tables on the link do not account for the fact that waste is constantly building up .... it only works it out on the basis of how many changes at a certain amount to reduce to a certain level, "and that assumes that no additional nitrate accumulates in the system during that time", where as mine attempts to compensate for that. If you feel interested, have a look, and see if you can use it. That parts where you are required to enter values are at the top of the screen, and highlighted in red / blue. Then, to see the results, scroll right down to the end of the page, and there is a box with "results" wrote over it, and they show the results. If you are not interested, I do not mind ....... sorry to have sent set a large file. If you are, then great, I would appreciate any views you might have on it. Regards Matthew Silvester (Co. Cork, Ireland) << NO3accumulation.xls >> <Interesting indeed... As a designer of such... am wondering what other "factors" come into play here other than dilution and time effects... Like the impact of the water changes, change mechanism(s) like gravel vacuuming et al. that might well effect nitrification... and the various different make-ups of gear, aeration, circulation... utilized... These are not empirical, anecdotal accounts/tallyings... but more mental exercise by author/investigator Craig Bingman... The upshot of which his opinion that a few more massive water changes are better than more frequent smaller ones... I do disagree... as there is certainly more at play here... namely "human nature" and the mal-affects of what massive water changes can/do imply... Instability and shock to livestock... much more than just serial dilution of a given material... Bob Fenner, who is ready for further discussion> 

Nitrate and conversion from fish to reef Dear Bob, I have a 90 gal. fish set up with 40 lbs. of live rock and 30 lbs of dead live rock having been treated with copper 6 months ago) and a wet-dry with a Berlin protein skimmer, also a uv with an Eheim canister filter. I would like to convert to a reef system so I took the advice in your many articles and took the bio-balls out of the trickle and added 40lbs of live sand. After 5 50% water changes my nitrates are still between 5 and10. Why can't I get them to ZERO. Please help. one frustrated reef wannabee <This may be the "zero mark" for the gear, type, amount, age of live rock and substrate you now have... You can/could very likely edge closer to zero ppm with the addition of: more substrate, possibly a plenum, the addition of live macro-algae... as well as adding the photosynthetic life you intend to as a reef aquarium... these will all easily "work"... and are detailed on the WWM site... under "Nitrate" and associated FAQs files. Don't be overly concerned now with the readings of 5-10ppm of NO3... not that high, easily lowered by the stated means. Bob Fenner>

Quick Biology Question on Nitrate Bob So my tank has cycled. Everything tests zero except for nitrates, which using the low range test of my Salifert kit, I get between 2 and 5ppm. I've done a 50% water change. At one point during the cycle, nitrates tested off the scale of my test kit (>100ppm), but they have obviously dropped off dramatically over the last three weeks. So I assume my rock has organisms which break down nitrate, correct? <In a manner of speaking, yes> This is the only explanation for the drop in nitrate. And to think, my parents spent $80K on my degree in biology from Johns Hopkins..... <You're making my evening> I have since added a couple of damsels and a small clean up crew. Amazing what a few turbo snails can do to a tank full of algae. So my question is with a tank full of organisms so adept at breaking down nitrate, will I ever see a rise in nitrate beyond say 10ppm?  <Yes, all being unequal... the "forward" reaction of nitrification (ammonia to nitrites to nitrates) "tends" to be more prominent in captive systems... with the conse- make that subsequent accumulation of nitrates> Is my low nitrate do to a new tank or the live rock?  <Hmm, both> I assume if I added a bunch more fish and fed heavily, I could get the nitrate up. But then I only plan on adding a couple of clowns, a couple of shrimp and a couple of anemones. <You are correct...> I wonder about this because I hear people mention much higher levels of nitrate and I only got to see that during the cycle. <A typical anomaly...> Thanks for the input Paul <Be chatting my friend. Bob Fenner>

Help (Nitrates) <Tom, Lorenzo Gonzalez here standing in for Bob whilst he's in Asia.> I hope you can help I have a 55 gal tank, using a emperor 400 filter, a sea clone skimmer, 2 power heads, and 40 lbs of live rock My tank is about 8 mos. old I change the water every 1 1/2 about 11%. I have 3 green chromis,1 coral beauty,1 tomato clown,1 panther grouper and 8 hermit crabs. I recently had problems with elevated Nitrate levels once as high as 100 ppm, what can cause this and what can we do to bring down the number?? <Nitrate is the final by-product of the nitrogen cycle, and can only be removed by anaerobic bacteria, or water changes. So you need either more live rock (best long term option), a plenum (impractical in an already-established tank), or more frequent/larger water changes. (Do this right away, if the Nitrate is still so high) > Please Help.. tom :) <As a side note - your panther grouper will eat all your Chromis, and probably your clown unless it's huge, as soon as he gets big enough. (They easily get a couple feet long in captivity) Best regards, Lorenzo>

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