I just bought a peristaltic pump that I will use to dose chlorine into the pool on a daily basis. I will just run it as a zone each morning for a few minutes. I will just adjust the run time to home in on a target chlorine level. I can set the time to run when my pool pump runs each day. This looks to be the easy part, other than having a 110v relay required.
For topping off the pool, I was planning to use another open sprinkler zone and add an additional valve to my sprinkler system and have it pour into the pool. I would set it to run for a set time each day, to counter evaporation, and have the run signal for it go thru a level switch that prevents it from running if the pool was already full from rain.
This is my current plan.