Trouble with nitrites.

[DBrossman]

So I recently replaced my whisper10i filter with a fluval u2 because I was having issues with not getting the correct filtration. My nitrites have been reading high with the 10i and lost some fish. Now the fluval reads no ammonia in the tank but the nitrites are high, and some nitrates. I just did a 75% WC and these are my readings after one day. I know i need to keep doing the PWC otherwise i will have dead fish but about how long should i expect to have to do the PWC's? In other words, how long does it take to establish a good colony of nitrite eating bacteria?

 

[Mrduna01]

Your tank is cycling and its sounds like your half way there. It varies but your probably a couple weeks out. Plan to do a couple water changes per day until your cycled. Did you seed the new filter with the old media? If not your cycle started over completely.

 

[DBrossman]

I could not reuse any media because the two filters used different media. Thank you for your help. Next time I need to change out a filter, I will definitely use the two filters for a while.