I'm in SOCAL (Inland Empire) and I use a solar cover. It will lose less heat at night, as the night temps drop significantly (I'm closer to the high desert) compared to the costal towns/cities.

I also use it, to prevent pine needles and other debris from falling into the pool.

I have a pool heater that I never used. I just bypassed the heater during my latest pool equipment upgrades and I will be disposing it. I'm almost certain that I will go with solar panels before the next swim season.