Thanks for the input, gmh, but I am looking for direct observations only. Hopefully we can find a definitive answer to this, although I admit to be a tad pessimistic.
The reason for the question is that Staghorn recently returned to my tank. Historically it has always been easy to remove by simply trimming plants or combing the substrate. But now it's found a home in my HC and HM which have become a tangled mess of plant and algae. The only reason it's established itself is because It's very difficult to remove the algae without removing the whole plant.
I run pressurized CO2 and dose dry ferts. I have only allowed my N to drop to zero once in the last month, and my Fe to drop to zero a few weeks earlier so I've been very consistent (well, 99% at least).