They were only out there for 8 weeks of summer time. Part of July, all of August and some of September. I put a dark hose in a coil in the sunshine and ran a slow pump through it...on Sunnydays it worked fine.
On cold nights I put in 3 300W heaters. I saw the water get as cool as 64 degrees on 2 occasions...both were 2-3 consecutive days of clouds and rain.
