My pond guy in Sacramento said my filter was "too clean" and it took me a month to get it
I was scrubbing my biofilter pads every Saturday for two years and couldn't figure out why my koi kept flashing. He asked how often I rinsed them and when I said weekly he just shook his head and said I was washing away the bacteria colony every single time. Now I only swish them in a bucket of pond water about once a month, and my ammonia has read zero for the past 6 weeks. Anyone else been over-cleaning their media without knowing it?