Here's what I'm thinking of putting in the pump-house of the Camp's 144,000-gallon pool, trying to feed around 1.3 gallons of CL per day.
Take a 55-gallon drum, maybe fit some clear hose from top side to bottom side of the drum as a sight gauge of the CL depth. Drill holes in one of the bungs, one for a vent hose (that'll go to outside the bldg) and the other for a bottom-feed hose connected to the strainer basket (suction side) on one or both pumps. Put a check-valve in as a precaution, and get either a fine needle valve or some other metering valve, and maybe even some sort of flow indicator. Since these pumps run 24/7, I'd hope that once I figured out the metering I'd be able to adjust it "High-Med-Low" according to pool use and basically keep ahead of CL demand/use.