We have a 30-gallon Indo-Pacific reef tank that we are just getting started. The system is currently running with live rock, and I'm adjusting my params. Thinking down the road a bit, we're researching corals for this tank. We'd like to start from the bottom up, so our first question is about the deepest coral in our tank that will live right on the substrate. What are peoples' experiences with Open Brain Coral (Trachyphyllia geoffroyi)? We have 4 inches of substrate. Other stats: 30 gal. tank tall tank with a Berlin sump, in-sump needle wheel skimmer, Current USA Outer Orbit w/moon lights (1x150w 10k HQI-MH/2x65w dual actinic/4 lunar lights), Sedra pump, Ebo Jager heater 75 watt, 54 lbs Live Rock, and 25 pound bags Sun/day sand. Thanks!