This year when we opened up our pool, we discovered that a critter of some kind chewed on our sand filter drain cap over the winter. It couldn't be fixed so we ended up having to get a brand new sand filter which cost over $1000. Our pool is going to be winterized tomorrow and I was wondering if anyone has any suggestions for me on how to prevent this from happening again. My pool pro suggested that holes could be drilled into a replacement drain cap so water can drain out but a critter won't chew on it. Does this sound like it would work or could the cap trap some water in there that could potentially freeze and damage the sand filter? Does anyone have any other suggestions on what could be done to prevent another critter from chewing on the drain cap again? We back to a field so we have a lot of critters around here that like to chew on things. I will attach a picture of the damage that was done last year so you will know what I'm talking about.