I have a few panels on the roof, and a solar controller. My current pool temp is 16C (60F) and according to the solar controller the temp at the collectors is 28-31C (85F ish). When the solar kicks in the water from the return is still cold, I notice very little difference between the solar being on or off. The temp on the roof panels also hardly changes weather the solar panels are running or not. It was working well when I drained it for the winter.
I am looking for ideas on where to troubleshoot.
Thanks in advance.