Ok, I do my water changes every single week, never skip. My nitrates and nitrates have always been at 0 but my ammonia won't go down. The tank is cycled, I have 3 filters already colonized with beneficial bacteria and yet my ammonia still stands at 0.25! Never had this before, usually if my ammonia spikes, a water change or two gets rid of it. But for the past 2 weeks, my ammonia won't go down! I've been doing 2 50% water changes a week...the tank is a 65 gallon cichlid growout tank.