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Cecil

Question about nitrites...

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Why is if I keep a moving bed going over the summer by feeding it ammonia, when I add fish to the system again, the nitrites always seem to spike? Ammonia isn't a problem and stays at zip but the nitrites will hover around 0.5 to 1.0 for a period of time before they come down. 

I don't think it's the fish load as the fish loads initially are quite low. 

I have to wonder if I shouldn't be feeding my filter something other than ammonia during the off season. Something that will mimmic the fish ammonia better? It would make sense to feed it the same feed the fish will get, but I don't want feed that will cause a mess and feed is more expensive than just adding ammonia. But maybe that is the answer?

Thoughts? 

Edited by Cecil (see edit history)

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Nitrites of 1 mg/l are most likely not a problem for the fish and are most likely coursed by the changing conditions.

Lots of things happen in biofilters; during normal operation heterotrophic bacteria are dominant, thus this different substantial from your situation during summer (feeding only nitrifying). Now the heterotropics can grow fast and will be present in low numbers over the summer, while the nitrifying bacteria are much slower.

Thus I would advice to keep doing what you do, but start adding fish food a week before you stock (no need to do this longterm).

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Thanks will definitely give that a try. 

Fortunately my species are also extremely tolerant of nitrites but it just bugged me I couldn't keep them at zero at first. 

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you might have a colony of microbes that are removing an oxygen ion from the nitrate and forming nitrite.

that is a more common path in nature, for example bacteria and e-coli do it in the mouth and gut of animals (including us) because it is a reduction reaction it requires very little energy. Maybe these microbes are killed from a ph swing or perhaps a metal in the fish food is reacting with any free nitric acid in the water when the fish are introduced back in the system. Reduction to nitrite also happens with the decay or burning of plant material or dead critters on its way to gassing off .

in a stable and diverse (soil) ecosystem there will always be some nitrites continuously formed, although with plants scoffing nitrates and other nitrogen compounds keeping the levels low  and storing it as amino acids, it takes something like a cold snap to throw things out of balance and spike nitrite levels.

if your nitrates are up for an extended period it is a possibility for sure.

 

 

 

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Thanks Yahoo. Good food for thought. 

 

Gary I always use NACL at 0.5 percent (5 ppt or 5000 mg/l )when I first have fish in the system. Then back it off to 0.2 percent ( 2 ppt or 2000 mg/l) and possibly even stop adding it if I am using the water for plants but not for a few weeks. 

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It's the Cl ion which does the trick on protection against Nitrite, while Na is the stuff the plants don't like; thus another Cl salt like CaCl2 will work without the ponic drawback. btw Calcium cloride is used for swimming pools thus easy available for reasonable money.  

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