jordangregory said:
Is there any truth to the claim that the clear covers allow more sunlight through and heat up the pool better?
Well, the answer depends on circulation. If the cover is very clear, then the water in the pool will absorb around 60% of the sun's energy turning it into heat, assuming the pool surface is white plaster. If the pool surface is dark, then 90% or more of the sun's energy can be absorbed. Of course, if the sunlight is getting into the water, so is UV and that means chlorine usage will be higher which is the main downside to using a clear cover.
A black cover will absorb most of the sunlight, but if it's an insulating cover it may not transfer very much of this heat to the pool water. Even if it did, you'd have to have good circulation moving water from the pool surface to lower depths. Otherwise, the pool surface water gets hot as does the cover and they radiate and convect a lot of the absorbed sun energy back into the sky/air. There are some black covers that are more clear on top and black at the bottom surface touching the water that theoretically should be better.
I have a mostly opaque electric safety cover so it's only about half as insulating as a bubble-type cover. I did notice a small increase in pool temperature rise when we switched from a tan cover to dark blue so the color does make some difference, but not nearly as much as opaque vs. clear or covered vs. uncovered.
The ideal cover for heating, insulation, and low chemical usage would be a very well insulated perfectly transparent cover to infrared and visible light but that blocked UV. Unfortunately, such a cover does not exist as far as I know.