Last night I checked the ammonia in the tank it it read 1.0 with liquid test. Added 6ml of prime Check the tank this AM and the plecko died. Tested water and .... ammonia is 4.0 nitrite between 0-.25 nitrate 0 I am going to do a 50% water change right now. I bought carbon and am wondering if I should add it to the filter media. From what I take from this is the tank cycling now?? This was the first time I used Prime had been using Ammo Lock and the Plecko last night was doing great before I went to bed. Some of the fish are showing signs of heavy breathing. Should I put the prime back in the tank after the water change or go back to ammo lock? I have both on hand. I have an aeration stone running now as well. tank temp 78 degrees.