Clark
Yes, Promix HP with extra perlite. However, I would not recommend it to most people, as it increases the risk of overwatering. That said, if you're careful and your environment is a little on the dry side like mine, it works great. I grew in bark for years and would occasionally buy plants growing in Promix. About 15 years ago, during the annual repotting, I realized that EVERY plant growing in Promix was larger than ANY plant growing in bark. I don't recall the numbers exactly, but I think it was maybe 10 phals in Promix and maybe 300 - 400 in bark. I immediately switched to Promix for all of my phals. I try it on other things from time to time, but the only other plants that like it are phrags. Oddly enough, I had a Cattleya schilleriana that grew very well in it for years and years before I chickened out and moved it to bark.
Mike