Mine looks like that too but they should really bubble up. I have moved mine to every area of the tank and it has never looked like a true "bubbler". I have it in the middle of the tank now and am just leaving it alone. If you look at pictures of others here that have bubblers, they look great, all full and extended. I only feed mine DT's.
DT's phytoplankton is not feeding your bubble coral. In addition to their photosynthesis, Bubble corals eat meatier foods, similar to other LPS corals. Try feeding foods like mysis shrimp, or tiny bits of meaty foods.
DT's phytoplankton is not feeding your bubble coral. In addition to their photosynthesis, Bubble corals eat meatier foods, similar to other LPS corals. Try feeding foods like mysis shrimp, or tiny bits of meaty foods.