I'm looking to build a sandbox for my daughter (18mos). I have a few questions for those of you who already have sandboxes:

What size do you have and are you happy with the size?

Where can I get sand - clean sand, I don't like the sand I've seen at Home Depot - it's very dirty. Also, I've heard about chemicals in sand that may cause cancer?? Anyone know about this?

Covers - I could buy or make one. I'd like to have some sort of mesh/fabric cover to keep critters out. Where can I buy this? Or where can I buy commercial-type fabrics for making my own?

Any help is appreciated!
Thanks,
Barbara