I did a 75% wc on both my tanks and I noticed this morning that my ammonia levels are up to 1 from 0. These 2 tanks are fully cycled and I never had this problem before. I washed/cleaned all the filters before the wc. I do clean my filters every 4 to 5 weeks. Anyway, I did 70% wcs back to back and ammonia is back to 0. All the other water parameters are OK.
No dead critters in the tanks and I am wondering where the ammonia spike comes from. One more thing, both tanks have bio-wheels and cleaning the filters should not cause this, I think. I will appreciate any help on this.
Last edited by a moderator: