Because I am heavy handed with the hose, I use a lot of lava rock. When I get orchids that are potted with sphagnum it could eventually mean trouble. Also taking sphagnum out can be difficult and harm the plant. So I pot the sphagnum in the middle of a bunch of lava rock. My thinking is that the roots will have their choice of a wet or not so wet opportunity.

Also I'm a proponent of orchids on the medium not in it for potting. And let the plant decide where they want their roots to go. So in the picture i did remove some of the sphagnum from the top.