Quote Originally Posted by BorisMD
Last fall, before close up, I added some citric acid, and partially drained and filled a few times to get the copper out. I also used a copper floculant, which produces tons of green copper oxide in the filter (cartridge), and requires frequent filter cleaning (big pain in the @$$).
I'm curious; what product did you use?

I'm wasn't aware of a product that would reliably precipitate copper ONLY on to the filter.

Are you sure the precipitate was copper oxide? The only copper oxides I'm aware of are black (CuO) or red (Cu2O). Could it have been copper carbonate, which is green?

Ben