Actually, on Tech TV, a dude coated regular beach sand with Kiss Cote, and I'll be damned if he didn't make a volcano shaped pile of sand, and poured water in it and it DID NOT leak through. This was not a promoter of the product either. It was on one of my favorite shows "The Screen Savers" about 2 weeks ago. I was impressed, until I found the website via a google search and noticed the price tag. I would be interested in trying it out, because seeing is believing, but not at that price!