You are much more of an expert than I am...but PHs pointed up? I'm not sure. This isn't a problem that I have with my acan lords. I have sand movement on the other side of my tank, but no sand on the acans.
Not to change the subject...but as my acan lords are growing I'm going to be gluing the frag plugs onto other pieces of rock. I know they'll spread to it, but will they end up making a domed look on their own or will they just stay more flat depending on the rock?