Came down one morning to find my dotty back dead on the floor of my tank and one of my two clowns missing searched around and found that my sally light foot crab was going to town on the clown :( later found out they were aggressive and not peaceful like the store said (should have researched more) . Took the two out and checked my parameters all was good but for some ammonia in the tank that I thought was to be from the fish being in there that night did a water change and seemed to drop down. few days later I noticed my one clown had spots on him (ich) so set up a hospital tank and threw some ceramic media from the tanks filter into a hob one on a 10g and started treating him. The problem I have now is that in both the hospital tank (10G)and the main tank (20G) they both have got allot of ammonia in them now and I can't figure out the source. The main tank hasn't been fed in almost 2 weeks and I've done multiple water changes on it but it just rises back up the next day. currently doing almost daily water changes on the 10g hospital tank just to keep the ammonia down. Can anyone tell me why there both full of ammonia ?I have't the slightest clue its almost like when I dosed with ammonia when I was cycling it.

(3 month old tank)

main tank is 20g

salinity of 1.025

temp 80 nitrate is 0

nitrite almost 0

ammonia about 6ppm id say

filter- fluvial 106 canister with filter floss ceramic media. - now has a imagitarium ammonia pad in it to help tank in some of the ammonia but doesn't seem to be working.

still new to saltwater and would love some help if you have any clue.