Should you leave the vinyl pool cover on when using a solar blanket or does the pool cover above the solar blanket hinder the solar blanket's performance?

Remove the vinyl cover when using a solar blanket to warm the water. If the vinyl cover is used at the same time as the solar blanket, the vinyl cover absorbs most of the heat and then transfers the heat into the air or water between the vinyl cover and the solar blanket. Then the heat transfers to the solar blanket and then, finally, into the water. When this happens, a lot of heat remains in the vinyl cover and air/water between the two covers instead of getting into the water. It is preferable to have the heat absorbed by the solar cover and then transfer directly into the water. Hope this helps...

Too much redundancy in pool covers.