Where did my nitrates go?

about 6 months ago, I started dosing nitrates and finally got some detectable nitrates. I got to as high as 20 so I stopped dosing nitrates and for about 3 months or so, I couldn't get my nitrates lower than 10. Back on 10/3 I tested my nitrates and got 8. I tested last night and now down to 0. How did my nitrates go from 8 to 0 in 3 weeks and it take 3 months to get from 12 to 8? I haven't done anything different other than my routine every other week 25g w/c.
Only reason why I decided to test my NO3 was because I was getting patches of cyano. When my NO3 was at 12, I had no cyano so I thought it was kind of an interesting correlation between cyano and NO3.

in english please

Nitrates are naturally eaten by nitrospirula (sp?) and as their food source is prevalent, so also is their propogation.

On the other side of the coin from beneficial nitrospirula, many other organisms process and metabolise nitrates as well as nitrites.

**edit ** mental f-up. AMMONIA to nitrites by nitrospirula, nitrite to nitrate by another bacteria, nitrate to nitrogen gas/cyano pooop slime

Cyano, macro and micro algaes, copepods, amphipods, and probably several million other micro organisms that have not been properly identified turn different phases of the nitrogen cycle into the next spoke in the wheel.

So, that being said, if the cyano had a good enough food source to propogate, they will grow. They eat nitrates as well as other wonderful things.

Increased water circulation as well as sand bed and surface stirring will result in the lack of cyanobacteria's presence.

Btw: trivia - cyano is actually invisible. Its waste is that purple slime you see. It is always present, but its waste is a sign that you need to increase water circulation, etc.

For sand bed, I recommend the elephant trunk snails (cant remember the real name... Cerith anails? Dwarf cerith?) they both stir the sand bed and will consume that cyano waste.

Maybe your sps has grown and is consuming more then it was before. Maybe you have fed a little less.


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I would guess you had a false reading on one of the tests.

Thanks for the detailed answer.
As far as the "more flow" to eliminate Cyano in certain areas, I'm not really a believer in that. I've had powerheads pointed at a rock that had cyano and after siphoning the cyano out, it came back stronger and more spread out on the rock.

Could be about the SPS, I haven't fragged in a while. And no to the feeding. My feeding regimen hasn't changed.

For all my reading, I used the RedSea kit and when it was 0, I borrowed my buddies salifert and it read 0 as well.

Did you double test your first result reading 8? Maybe it was already 0...? I have read negative things about redsea tests, but everyone swears by a different test. For me it is Salifert.

at that point, no I didn't. my test kits were only about a month old at that time.

Despite all the good praises everyone gives red sea. I could sware that everything I buy from them is the dud.

I *seem* to do the tests right, but then I'll go in and check the same samples in the lab, and come out with up to 20% differences in either direction.

IMHO, seachem, while quite a bit more ergonomically difficult to use, has come up with surprisingly more accurate test results against what I later test in the lab.

Hanna checkers are the best, if you can afford them, which at the end of the day, they will end up costing you less.

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Great post. Lots of interesting issues to comment on. First, Cyanobacteria often proliferate with zero or undetectable nitrates. They have a biochemical pathway that gives them an advantage in that environment ( I believe they can utilize N2 when NO3 is limited). So it is often reported that low nitrate tanks sometimes end up with a cyano outbreak. I presume other competitors or bacteria are outcompeted in that low nitrate environment

As for where did the nitrates go. Just some thoughts, it seems that months ago when your nitrates were low and you required supplementing them, that you may have ultimately accidentally overdosed. Some reefers report that they add and add nitrates and then all of a sudden that nitrate deficit is finally made up and dosing needs to be reduced substantially. So maybe that original deficit was overshot and now that very efficient nitrate processing tank has finally worked through the overdose and now once again requires supplementation. Akin to carbon dosing, you need to find that happy zone of adding enough but not too muchor too little. So I expect you'll need to once again dose substantially for a while, test frequently and then cut back to a maintenance dose.

Aside from the above discussion, I remain confounded by the change in nitrate levels found in tanks today vs 5-10 years ago where high nitrates were the norm and the challenge was to remove them. Skimmers have gotten better but I'm not convinced that much better--and if you are a bubble king fan, there has been barely any improvement. Rockwork has been reduced in that time--negative space. So all that rock with bacteria capable of nitrate processing has been reduced--although who knows how little rock is truly or absolutely necessary (my tank is old enough to be old school and I like all the extra real estate for sps colonies). Lots of tanks are bottomless so the sand bed as a nitrate processor has been reduced--unless of course sand as a detritus collector may ultimate serve as a nitrate producer (I keep sand but would remove it if I thought I could reach the back areas of my tank). I understand siporax and use it, but not everyone is utilizing it. Same with carbon dosing, I understand its methodology in nitrate reduction, but not only is it not universally in tanks but I think it is not as popular as it once was (for the record, I don't carbon dose). And water changes haven't changed much, some people do 10-20% weekly changes and some don't change water out at all(I'm in the former camp). Yet more and more comments about people needing to add nitrates on reefing sites. I find this trend both interesting and confounding. And I dose nitrates (KNO3 powder) to keep my nitrate levels between 5-10 ppm. Who would have thought...

[MENTION=3886]watchguy123[/MENTION], how much nitrates are you dosing? When I got to my highest NO3, I didn't think that I would need to do maintenance dosing of NO3 because I would let it fall naturally and then when I got to 5, I would start up dosing KNO3 again. When I was at 8, I told myself to test every other week so that I could start dosing once I got to 5 but I missed a week and when form 8 - 0 in 3 weeks. But now, back to dosing KNO3.

The answer may surprise you. I couldn't wrap my head around using spectracide stump remover so I found some KNO3 that is marked USP and FCC which should mean it is food grade and reasonably pure--I tried to purchase some much more expensive grade but they would not sell to an ordinary guy, only research lab. Any way, I use the spoon from a salifert nitrate test and found that adding six level spoonfuls daily keeps my nitrates around 5ppm. I still need gfo to reduce phosphates which I am somewhat confounded about. Assuming some relationship to redfield ratio, I would think my phosphates would come down. I check phosphates with a Hanna ulr phosphorus checker and even with gfo, I tend to stay around .07ppm phosphate. I understand that phosphates are related to primarily food added and can deposit into live rock and sand beds but I have almost no visible algae in the tank--wipe the glass once a week when a super light algae coat develops and probably could go much longer without wiping glass. I utilize a refugium with chaeto which is very productive and I also utilize as previously mentioned a skimmer, water changes and 11 liters of siporax in an approximately 180 gallon tank.

Back to your original question, I've never tried to calculate what my six spoonfuls of KNO3 adds in ppm daily to my tank. Should be interesting to calculate what that number of ppm of nitrates actually is. Any idea how I might do that aside from measuring nitrates immediately before and then after addition. I use Red Sea pro to test when under 4ppm and salifert when 5ppm and above. But I find salifert inexact in that I often am challenged to see a lot of difference between 5 and 10 ppm even when looking through the test vial through the side.