Amanda- I was thinking….(watch out! ) If you have to add water with a hose, and then take out water when it rains…why not place the barrel on the edge of the pool or raised a little nearby and drill and cement/caulk and put in a spigot (plastic). Take water out into barrel, when low, open spigot and with or without a hose (depending on where located) add it back. Now I don’t think a single 55 gallon drum would work as I sometimes discharge much more I think (30,000 gln pool) (not big enough – but could be wrong) but you can easily connect them with plastic flexible hose near the top like I do my rain barrels (they aren’t caulked etc in that instance). You can add as many as necessary. just be sure the barrels have lids – mosquitoes and bugs and algae oh my!. Just a thought.