If you live in a cold climate where temperatures reach below freezing, it is highly advised that you fill your hoop base with sand, as water expands when it freezes, which will cause the base to warp, crack, and even fracture completely. Regarding the right sand to choose, dry sand — as opposed to the “play” or “multi-purpose” sand like you’ll find at Lowes or Home Depot — is typically much easier to funnel into the base. You can put your sand into a large bucket and let it dry in the sun for a day or two, otherwise it could take hours for the sand to slide down the funnel and through the small hole in the base.