DIY EMT Solar pool heater

I would not use EMT. Pishta I KNOW you are a smart guy have you google searched efficient solar collector designs? I once played with the idea of building something. The truth is I don't care, anymore. The sun energy "up here" in the N end of Idaho is a LOT less than down there, so there's that.

But there is certainly differences to be had in design. Also don't forget that if you don't have a method of drainback, the system can radiate heat OUT of the system at night as well LOL