Ammonia spike?

Question

I've been cycling a 20g tank for a little under three weeks now, with three danios and five white clouds. Over the last three days, my ammonia, which had been hovering at around 0.25 ppm, has suddenly risen to about 0.5-1.0 ppm. I'd been doing 25% water changes about twice a week, although I'm doing them more frequently now with the higher ammonia. I also feed the fish a small pinch of food every other day.

Is this my long-awaited ammonia spike? If so, how soon should it take to go down to 0 (it's been spiking for about 3 days now)? Also, my substrate is sand, with a little gravel mixed in. Do tanks with sand take longer to cycle?

Answer 1

Yes it is a spike.Keep a close eye on it.Anything over 2ppm will kill just about anything.It will take a week or 2 to drop back to 0ppm.In the meantime the nitrites should also be rising.These usually take longer than the ammonia to drop back to 0ppm.Im just guessing,all tanks are different,but it will probably be another 4 or 5 weeks before the cycle has finished,and you can add more fish.The substrate does not effect the length of the cycle in any way.

Answer 2

You are doing a great job with your tank! The ammonia should start to decrease in about a week or so. It may take 2-3 weeks or longer for the ammonia to completely disappear.

Twice weekly water changes should keep that ammonia under control.

Answer 3

This is not too long for a cycle with fish. Now begin watching for the Nitrites to do the same thing. The nitrobacter bugs that eat the Nitrites can't begin to grow until the nitrosomonas begin to make significant amounts for them to consume. The substrate doesn't make much difference but the more porous it is,the denser the bacteria populations will be.