Growing medium
Gastil (Thu, 12 Jul 2012 12:18:48 PDT)

The Dry Stall website faq says it weighs 28 lbs per cubic foot.
Water weighs 1000 kg/m3 which is 62 lbs per cubic foot.
So Dry Stall should float on water.  Does it? 
If so, then Dry Stall pumice is more like the pumice I am familiar with, 
more like Perlite than gravel.