I have a 20,000 gallon Gunite pool in the Boston area, I have a 250,000 BTU Pentair NG heater - works great. My pool filter/heater are running 9am-9pm. Would it be more cost effective to keep my heater ON set a certain temp rather than firing the thing up in the AM to get the pool up to temperature?

We use a solar cover at night and lose very little temp (weather permitting).

On the rainy/cloudy days I would of course turn the heater off...

Thanks
Dave