ok try changing out the ammonia media every 3weeks bio media the next week and carbon the following week. but never all at once. and when doing a water change use stress coat to remove chems from the water just add it to the water then add the water to the tank 2mis later. also you shouldcheck your waters ph and ammo levels at lest 1 a week just to keep up on it. i also use AC 500 on my 55 with a wet dry so i hope this will help you good luck.