Do not put dendrophyllidae on the sand bed if you have fine sand!!!!!!!! Sand irritates the polyps. All of this family will not be on the sand in the wild, as they hang from underneath rock cliffs. Even if they're right-side up istead of upside down, a nice rocky, shaded area with enough flow to keep it clean of debris(again, upside-down in the wild takes care of this) but not enough to shake the polyps too much would be ideal...also when you clean debris off of the coral, do it when the coral is closed.
These are my experience with them, but that could be different for everyone. Especially now that many of the dendro family(including, but not limited to dendrophyllia, balanophyllia, ryzotrochus, some tubastrea and turbinaria, etc.) are now aquacultured. Times, they are a-changing.