Phrag kovachii was discovered growing on Lime stone hills, I am guessing conditions are not far from that of Phrag besseae. There are natural springs of fresh water running down those tall slopes. I suspect, these plants are intolerant of stagnant water. Also, it might not be a bad idea to eat some Oysters, clean the shells and placing pieces on top of the medium.
Btw, coming back to Phrag richteri -
I repeat "I had to look up Phrag richteri. It is a natural hybrid of boissierianum × pearcei." No Phrag Grande involved here.
I keep a Goldfish pond, so in Summer I was floating the Phrag pearcii in this special island, where it got super well watered and pampered. I thought that might keep it happy.