cycle mystery

[tdavila3]

I have a 20 gal freshwater tank that i am cycling with fish and everything was going great. My ammonia dropped to 0 and my nitrites had started to climb and Nitrates were yet to register. That started on last week and as of sunday 8/25 the nitrites were around 1-2 ppm so i did a 25% water change. I checked all of the levels today and everything is at 0.

is that desirable or did i mess up somewhere?

[Cliff]

Ouch, 1-2ppm of nitrites is very high for cycling with fish. I would suggest keeping the ammonia and nitrites at 0.25ppm as they are both toxic to fish. Base the size of your water change on your test results when cycling with fish. If your nitrites were at 1 ppm, then you should complete a 75% water change to lower them to 0.25ppm.

However, when cycling it can be normal to see the nitrites get then return to 0ppm as you grow the nitrite eating bacteria.

Keep a close eye on your parameters. Once you start to see the nitrates increase, you should be cycled

[Stlouisfish]

+1 with Cliff. Don't get too comfortable seeing 0 ammonia that you don't check your nitrites - you don't want another spike like that with fish in there.

The one of the points of water changes while cycling with fish is to remove things we don't want in the water that can harm them- the higher the level of toxin, the more water we need to remove at one time to lower the level.

While cycling, you need to maintain SOME ammonia in there to grow new bacteria and feed the existing ones, therefore, it's recommended to keep ammonia at .25 until it drops itself to 0 and you get a reading for nitrates.