Jhn

I have tried the black out method for 3 days and kept the areation going but it is still alive. My nitrates are 20 ppm.

Gunnie

Beef up your water changes. If you do water changes weekly, try bi-weekly.

voiceless_kat

I had this problem in a betta/cory tank, and was doing water changes every 3 days. It slowed it, but today I gave up, removed all of the substrate (with fish still in tank), cleaned the couple of decs left in there, and replaced gravel with glass flat marbles and glass shells. I scrubbed all the corners and bottom of the tank with my cleaning brush. Hope it works, it is a pain in the butt!!