Perlite is available in a variety of sizes from almost any garden center or nursery. I like to get the the biggist (largest chunks) I can find, but sometimes you have no choice. Is worth getting. :thumbsup:

re sand: I used to toss in some greensand for the minerals and iron it contained. Been a long time since I used it...but doesn't greensand buffer the soil, too? Wish I had kept my old logs...
Anyway, it didn't take long to switch to the easier-to-control liquid micronutes.