Poorly growing/dying plants are the ones I am trying in SH..so far so good. I am actually seeing improvements in these plants. I have phrag seedlings, a couple of paphs and one phal bellina ..probably would have tried more but I ran out of "rock". I don't know the kind of rock I had either. It was in a bunch of supplies that was given to me. Somewhere on RVO is a picture of the first ones I did...A friend that is a SH nut says struggling plants do better than established ones.. Good Luck !