HI everyone, I made a separate post a few days ago about some fin rot on my angelfish and discovering that it was likely caused by an ammonia spike. I thought it was due to overfeeding, but I have cut down the feedings in that tank, still no luck with getting rid of the ammonia (even after yesterday - my big water change day), and now my other tank is showing higher levels (both tanks now at 0.25). These tanks have both been up and running for over a year, both are 29's. One has an oranda and a telescope, one has a (very) juvenile blood parrot and a juvenile koi angelfish. Both have Sunsun 303a canister filters, but I just added intake sponges to both, one minI sponge filter to the goldfish tank, and 2 minI sponge filters to the other tank. I've been doing daily water changes between 30 and 50% (except yesterday I did my usual 90%, as I do that every weekend and have for over a year with no problems) and dosing with prime and Safestart, which I know a lot of people say is pointless, but I figure it can't hurt any more than the ammonia spike. I'm really trying to deal with the fin rot here, which isn't any worse but definitely not better, but I can't find the source of the ammonia spike! Could old filter floss cause problems (I don't change it very often) or even could the new sponge filters and intake sponges be causing a mini-cycle?