On 5 Jan 2009, at 18:25, Justin Smith wrote: > I wanted to change to pumice but that was not available here so i got some > lava rock from Lowe's and crushed it up into smaller pieces. The lava rock that's widely sold as a garden top dressing is nothing like real pumice. Pumice is porous, solidified rock foam, and quite water retentive, whereas the lava rock isn't water retentive to any great degree. This charming fact means that you can plan next summer's vacation now: plan on visiting Crater Lake in southern Oregon. The access road along Annie Creek to the Rim Drive climbs to the caldera rim over enormous deposits of pumice, and along US Highway 97 which runs up the east flank of the Cascades, NE of Crater Lake you go for miles through drift, banks, and hills of pumice thrown out by Mt. Mazama when she lost her temper some 6000-7000 years ago. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island http://maps.google.ca/maps/…