Hi, I am rather new to the hobby, and I have been having problems with the cycling in my 10 gallon tank.
The tank have been established for 3 months, it contains live plants, a betta and 4 corydoras pygmaeus (used to be 6, lost 2 due to cycling problems). I have waited until the fishless cycle was done to add my first fishes (always in pairs) and all was good but about a month ago, I made the typical newbie stupid move of washing my filter's foam in the tank's water, which apparently was too early to do for a small tank and debalanced my cycle. I was advised to do partial water change every 2-3 days until it evened out, problem is, it DOESN'T even out. I've been doing this for nearly a month, I test every 2 days and I always get 0 ammonia, 0,3 nitrite and 10 nitrates, I haven't touched the filter nor the substrate since my blunder (I use a turkey baster to clean up leftover food, that's all). Once last week, I got a 0,1 nitrite after 2 days, but by the 4rth day it was back to 0,3, and never happened again since then.
I'm puzzled. I know I must be doing something wrong, but I can't for the life of me find what it is
The remaining fishes seem unaffected so far but I know nitrite is a slow killer so I really need to get this under control and quick!
Thanks for your help :)