To answer your question solar heating is not real effective in the North East, think gas heaters are most used.
A dark pool bottom/sides would aid in keeping it warmer...midnight blue or something like it. Seafoam green sheds light, so, cold, but a dark forrest green would work. The typical light "pool blue" is hard on the eyes when it's bright out and it's not really conducive to warmth, either. Black, if you wanna get your freak on.
Ummm no, the heat from sunlight is released in the first couple inches of water, it never makes it to the bottom of the pool.
I beg to differ. Every dark pool I've ever been in has had noticeably warmer sides and bottoms when exposed to the sun. Dive in, feel the bottom for yourself.
Then educate me. What would be the reason? I'm pretty sure the laws of physics would state that a cement hole full of water whose surfaces are dark is gonna absorb more radiation from the sun, than one with light-colored surfaces, and conductively transfer that extra heat. The first time I felt it I knew I would never have a light-colored pool...their sides are as cold as the water.
The reason is simple, you're delusional FWIW I think you're right, the heat of the air will not transfer but as long as light is reaching the bottom/sides there is no reason why the rays wouldn't do something.
Roughly 5.5 degrees of difference at most. And that most is probably 1 degree too high. That is comparing a white pool to a black pool.
Refraction isn't reflection and the material that is the "liner" will have an effect. Is this liner paint/tile/gunnite or is it as it sounds, a synthetic liner that simply provides a waterproof membrane like in an above-ground pool or cheap fix for an in-ground pool? I wasn't wrong with the air in the truck bed. I just didn't elaborate to say that same pressure (weight) was also pushing up from beneath. It's 14.7lb/sq" all around.