Hi, and thanks for the reply.

Well, if we can just kind of forget it is a pool and consider it an above ground pond, that seems to work better for most people. I would not be able to use the existing pool pump or filter, as filtration of a pond is a whole different animal than filtration of a pool. I will be making a biological filter (huge) from a stock tank. The sand filter would just clog immediately, and the pump is not geared toward moving the volume of water the right speed for a pond. So, in short, it will be filtered, but not with my pool equipment.

My main concern right now is is anybody knows how far down an above ground pool freezes in the winter. There would need to be some liquid water for the fish. I do believe that even if the whole 4 feet of shallow end freezes solid (which I doubt it would), at least the 2 feet that are underground in the deep end would remain liquid. The fish could go there. I will be having Koi, goldfish, Shubunkins, and/or a mixture of all. Not quite sure yet. I will keep a bubbler/aerator going in the winter, but turn off the main pump/filter unit until Spring.

It's just a thought in progress right now, but I am getting more excited about it the more research I do. It won't look like a landscaped inground pond like yours does, which I'm sure is beautiful. But I will be happy to have fish and lots of lillies, water hyacinths, water lettuce, cattails, etc.

Thanks for the input. I am going to call the pool place and ask about a main drain cover.

Have a good one!

Sandy