Sorry, I looked over other threads with sizing questions, and have not found a good formula for helping to determine which size SWG to purchase.
History - got a new 19,000 gallon (approx 39x16 up to 8' deep) pool in May. I live in Georgia outside of ATL. Current weather is mid to upper 90s air temp. Pool gets pretty much full sun from about 8:30am - 6pm. Before I added some water jets to the returns, the water temp was into the 90s. With the jets running at night the water temp is about 78 in the morning to about 82 by night fall. Knew little about SWG and relied on installer, who put in an Eco-matic ESC6000. This unit is not keeping FCL even at 1ppm and reading up on unit, it would seem to be grossly undersized for this area. So I want to replace that unit with something better.
So from research and reading reviews here, I am leaning towards the Autopilot Pool Pilot Digital or Total Control.
 Deleted a couple of questions as I found good info on the site - thanks.
A question is what size to get. I am "thinking" the RC-52 would be good and oversized enough. From my conditions, would that be a good size/still pushing it/too big?
Thanks in advance. I wish I had done all this research before the install, but we were anxious to get installed, and didn't realize the complexity of the selection of the SWG.