We only have a small inflatable pool, but I spent so much money filling and refilling it last year when it got dirty and I just hate wasting water like that, so I'm attempting to save the water this year.
I moved our pool to our deck instead of the grass(it doesn't kill the grass and keeps the grass out of the water that always sticks to wet feet). I put those puzzle like foam pieces underneath it so its still cushion like underneath.
I have it in a corner of the deck and bought a tarp to lay over it. I tied one side of the tarp to the deck rails to anchor it. When its time to get in we just flip the tarp over the side of the rails. Viola! Instant cover.
