I've had 3 larger (3-4" now) purple digi that have great vertical growth, but have shown no signs of encrusting at the base. They have been in the same spot roughly a month and a half, in a higher flow area of the tank. I also acquired several more sps about two weeks ago and they are already showing encrusting, is this normal for digi? I've seen a lot of encrusting from other threads and online sites selling them, I assumed I'd see some type of encrusting at this point.