Jo, I use the "Better-Gro" Special Orchid Mix for most of my plants. It seems to be the best that I can find around here, we are very limited in this area for this type of orchid medium. I have found that the bark quality varies from batch to batch, occasionally some is very black and started to break down to bright and fresh and in between. The one thing I do now is heat treat it in oven before I use it, as I found that snails were showing up in plants that were not exposed to conditions where they might be picked up.
I can get more consistent bark base potting material on line but the shipping cost is more expensive than the bark, so only use that method for the fine base bark.
I use MSU fertilizer and reverse osmosis water every other week.
