Hello, I'm about to remove the leaves from my pool, and check the chemical levels before putting my pool cover on it for the winter. Right now, the water level is very close to the top of the skimmer hole, because of all the rain we've had. Is it advised that I should lower this level before covering it? If so, why is this advised? I should mention I live in Austin Texas, so the winters are mild here, but I see there is some below freezing forecast for later this week.