With my tax return, I'm getting a portable basketball hoop with a 31 gallon base. The FAQ for the hoop says the base will expand if water is used and it freezes. I'm not 100% trusting of that but sand would cost me $25ish and a backache. It would also be much easier to empty it of water then sand if I ever had to do that. I've never owned a portable hoop so just looking for advice from anyone with knowledge. Thanks.