Cycle question - how do nitrites drop?

billswin

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Dec 15, 2009
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I think I know the answer but not positive, I am currently in week 4 of the cycle process, I have 0 ammonia, off the chart nitrites and 10 nitrates last time I checked them about a week ago.

My question is that the nitrites have been high for weeks, will they drop over night to 0 or gradually drop or do water changes need to be done to lower them?

I am under the believe that they will drop from 5+ to 0 but it seems crazy?
 
They will hit 0 overnight. If you haven't checked in almost a week, they might have dropped already
 
I agree. The nitrosomonas bacteria do grow exponentially, so technically nitrites will drop exponentially. Mine went from 5+ ppm to 0 in about two and a half days. Towards the end of the cycle I noticed differences with q12 hr testing.
 
so I should not change the water the nitrites are still showing at 5+ppm - 2 of the fish are hanging near the top.
 
the benificial bacteria live in the filter media, the gravel/substrate, and on the glass and decorations in the tank. you can change the water and lower the nitrite count for your fish without negatively affecting the process of the cycle.
 
How fast Nitrite drops depends on tank as I have seen some took as long as few weeks. Meanwhile prolonged exposure to such high level can be detrimental.

Unless it is planted tank, adding salt will reduce nitrite toxicity.
As far as fish exposed to such high nitrite, this does pose threat to their health/longevity, even if fish survive such exposure.

I would perform small but very frequent water changes until reduced to lower levels (hopefully below 1). Do not disturb the gravel nor filter media when peforming water changes until well cycled. Cut down on feeding.

Nitrite inhibits gas exchanges as it can bind to exchange site on hemoglobin or equivalents thus reduces gas exchanges meaning CO2 will accumulate in the blood causing ACIDOSIS, drop of blood pH. Very similar to carbon monoxide (CO) poisoning on us. More complicated than how I explained but no need to go any further.

Use the salt as it will reduce ionic nitrite. Just follow the instruction on any Aq Salt.

Hope all goes well!
 
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If you have fish in the tank, stop messing around and get your nitrites under control while they are still alive. The tank will cycle whether or not you can measure nitrites, but the fish won't live very long with high nitrites.
 
I would do a 50% change immediately! Make sure to temperature match and treat the water with dechlor. If you're using prime, it's okay to overdose... read the bottle for "emergency situations".

Then follow that up about an hour later with another. Do whatever you need to do to get the nitrite down. It's very toxic to the fish at that level. And as already suggested even if it doesn't kill them immediately, it could seriously effect their long-term health.

However I do also want to take a moment to say good for you for caring enough to join a community like this and ask questions! Good luck with them!
 
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