I was just reading the manual for the skimmer and it says to drain 6 inches below the returns (like TFP recommends) but then it says to remove the eyeball return and put in a threaded cap plug. Why do you need to do that if the water is drained 6 inches below? Since I will not be the one installing the pool & skimmer this spring I'm worried about taking it off and putting it back on. Can I just leave the eyeball return and skimmer in place all winter?