ZipLock bags for play-sand

[Watermom]

I think Walmart sells them.

[ChuckD]

Not sure how big you're talking about, but take a look at those "Space Bags" that you store clothing in and suction the air out of. We've got a bunch of them in different sizes and like them a lot.

[knarf#2]

I tried these large bags (among other things) to weigh down the stairs, but I kept getting sand in the pool. Somewhere in this forum there's a great suggestion using several PVC plumbing tubes filled with concrete and capped. This has worked great for me to weigh down the stairs.