I care about it for the chloramine on the new water, I'm not worried about the rest.

I realised there is a "current" in there today. When we first got the fish, they swam in circles all the time. As I added pumps, they stopped. They are still swimming, just the water is passing by while they stay in place most of the time.

I'd say the whole pond gets pushed to the top of the rocks and runs the filter path every few minutes. The bottom of the rocks is a 6 inch drop so it aerates as well. Pushes up the local ion level. People love hanging out at waterwalls for that.

M told me they responded to the tapping before feeding by coming to the surface and swimming to her side. I thought they were, but I was waiting for someone else to tell me in case I was imagining it.