I've really been wanting to figure out how to do an auto-makeup system for our pool. Years ago on a family pool I managed to fab up something that basically used a toilet valve with a PVC line going from a hose into the skimmer, however my new pool doesn't have a hose outlet anywhere near a skimmer so that idea is out. There is a outdoor water supply very near the pump which I was thinking perhaps I could run a line from that into the pump room, and put a fresh-water inlet somewhere.. thinking just before pump entry , or perhaps work down a tee into the pressure gage fitting somehow?
Then use a combo of an electronic float swith in one of the skimmers wired to a servo valve.
Obviously there'd be a fair amount of "design" work to get it all sorted out, and decent looking but it seems like it should be simple enough.
Any reason it's not OK to run makeup water into the pump plumbing? Only alternative would be to somehow get underground pipe all the way out to the skimmer but that would be a pain.