I have read a lot of pros and cons about heating a pool for all these three. I have to replace a rusted out Natrual Gas heater and in my reserach it seemd a Heat Pump might be my best option for Toronto Canada. Any thoughts on this as well as other options - Solar and return to Gad.
I am curently looking at Aquapro 800 for my inground (~24,000 gals), salt water pool with CPO rating of 6.2.

Thank you.