DIY EMT Solar pool heater

I'll also suggest going with the solar cover, too. At one time I'd planned on making something similar out of copper tubing and some old windows I had stashed away, but I was worried the chlorine in the pool water wouldn't react well with the copper, and I can't imagine galvanizing on the EMT would work any better.

The cover I have looks like really heavy duty bubblewrap and works great. It warms the water in the daytime and keeps it from evaporating and cooling at night.