It's a lower light piece. You also need to redirect your flow. Your getting high nutrient areas which cause cyano bacteria to prosper. Need more uniform flow. Encrusting Monti's low. Acros high. Milli's high to medium. LPS low. Plating monti's , Medium to high light, away from other coral. Your's will be covering valuable space and reducing light for other coral when it grows out.
How many gallons?
Those snails can't right themselves.