We recently moved into a house with a small decorative pond. This will be the first winter we'll be going through with the pond. I'm estimating it's about 250 gallons. There are no fish or plants - just a waterfall feature and purely decorative. Last winter it got really cold here in the Baltimore area. I'm sure this pond would have frozen solid. I'm assuming it's a bad idea to leave the pump in the pond if it's going to freeze. Is removing the pump the only thing I should be worried about?