Pumice
 

Has anyone used just pumice? I'm specifically curious about Akadama "hard" and "baked".

I use pumice - just regular horticultural pumice I've gotten from hardware store or nursery. I use it in bark or chc mix, mixed with just perlite, or alone.

Akadama is a granular sandy to gravely substance used in Japan to pot bonsai and other coarse soil loving plants like camillia and azaleas, It drains readily but because it is somewhat porous it retails moisture in the very small capillaries. Like agricultural pumice but harder. It is good for orchids because it drains completely but stays moist. I use a cinder/lava rock for some of my orchids. I pot phals and catts in it and have had success with oncidium intergenerics in it also. I get it from east of the the sierra nevada mnts in Calif. I sift it into different grades. I also get a more highly aerated pumice from the same part of Calif only farther north around Mammoth Mountain. This stuff floats on water it is so full of holes but is really good with Catts. If you have access to akadama I would try it with catts first and if you like it try it with phals. What I really like about it is the fact that because it drains so quickly I can water much more often without the fear of root rot and because of this I can fertilize more.

I'm just looking for the ideal medium.

I have seen Akadama but not in the size I want. While looking online, one vendor had a couple of heat treated ("hard" and "baked") kinds. I asked them for more info in the difference but only got what was on their website. So I thought I would ask here.

I've done OK with lava rocks and hate perlite(does anyone worry about silicosis?) almost as much as I hate sphag. I have some plants in 100% Hydroton but am either trying to keep the plants from shifting or chasing after the rolling balls!

Akadama looked more porous than hydroton, less porous than lava rocks and harder than hort pumice, I thought it might meet most orchid needs. I really want to get rid of the 3 crates of different media I have.

That online vendor's shipping cost makes them prohibitive to order from. I'll have to keep my eyes open for potential bonsai supply places.

Edit to add: I have one NoID catt in all hydroton and no phals.;)