I have an ancient pump that I can drop into the pool to keep the level in check under my looploc mesh drain cover, but it takes hours to drop the level a couple of inches. Is there a good, high flow 115v pump I can leave in there? I'm wondering if I should get one with a built in float switch, then I can leave it on my steps at the right level (15" below deck edge), or just drop it in when needed. If it's always submerged, it shouldn't freeze up in cold temps either.