Brian, pumice floats. Actually, not enough to skim it off either, but it doesn't settle at the bottom, which would make life a lot easier if it did. Ina On 4/07/2013 11:14 p.m., Brian Whyer wrote: > Just swill it around and pour off the organic and fines. The grit stays in the bottom. > > Brian Whyer, UK -- Ina Crossley Auckland New Zealand zone 10a