substitute Pumice for Perlite in 5:1:1 mix?
Is it ok to use Pumice instead of Perlite in Al's 5:1:1 mix. I've been buying it in 40 lb bags (called Drystall and sold at horse/farm supply stores). It's a bit more expensive than Perlite, but looks like it would last much longer and it doesn't seem to produce the fine(inhalable!) dust that Perlite does.