re: Pool Chiller Purchase

Pretty sure there are two main kinds. There's a heatpump style that looks like an air conditioner. That moves heat both directions depending on your settings. Dumps pool heat or adds heat to the pool.

Then, theres an evaporative cooler style that cools the water with a fan as it percolates down through the body.

Heat Pump style will make the water nice and cold.
Evaporative has a limit due to our humidity that I suspect gets into the wet bulb temperature of the air.

I hung a big triangle sunshade over a chunk of my pool and added 1 of those return jet fountains. It doesn't work miracles but my pool was at least 5 degrees cooler last summer than my buddy down the street. (All for $150 mostly in stainless steel cable and parts)