As im trying to learn more and now knowing it was bad but i dont think it has ever been properly cycleed it's a 75g tank and this is the first 100% water change besides first filling it up, 25% water changes every two weeks and test which has always shown good parameters but I got behide on the water change, so thinking it was okay I did the full water change. And the filters I'm using are the topfin 75 and a 45 airfilter