water changes as well? Or no?
I'm not trying to seem like I am second guessing anyone, I just want to make sure I'm getting it right. I have had tanks my entire life and never had issues like this before.
Yeah I'd keep doing the water changes if ammonia is present. I've quarantined rare loricariids with daily water changes (50%) and no filtration at all. Kind of a pita to to it that way but I found a fish I wanted and had to have it even though I wasn't prepared.
Sounds like something caused your tank to cycle, or at least mini cycle again. Even if the system has been setup for 6 weeks, it's still very immature and fragile. Stability takes the guesswork out of the equation and cycle your tank with stock quickly and safely.