I just got a Fafco solar heater for a 24' round AG. The two things I like about it are 1) it's a single 4' x 20' panel so less plumbing and 2) it's got a built-in bypass valve. It sells for around $200. I notice that this mat uses small tubes placed side by side so the entire mat is used for water heating. I have it on the ground on one side of the pool. The water temp went from 62 yesterday morning to 68 (first sunny day in a long time!). I start to get shade on the mat around 3 PM so I think that's pretty good.

Peter