When is it necessary to remove a solar blanket from a pool and is removal necessary to maintain oxygen levels in the water?

A solar blanket is an inexpensive way to heat your pool water. It should not stay on during the of season. I recommend a winter pool cover. However, the heat fgenerated from the solar cover absorbs a significant amount of chlorine and tends to lower the Ph level in the pool. I suggest you regularly, atleast once a week, check the chemical levels in the pool water.