We've added plain old milled Canadian sphagnum moss to our Paph/Phrag mix for years. Not sure of the company name, but we get ours at Home Depot. If your water quality is good, you'll grow a nice mat of moss on the mix surface. Usually takes about 6-7 months for this to happen with our mix formula. Once you have a nice moss mat growing, you can tease it apart and add it to the surface of other pots where it should grow quickly to provide that extra small amount of amine compounds for the plant roots. Living moss is a great cultural indicator as well; if the moss is not growing well, there's a problem w water quality or over-fertilization.