I have two other corals in the tank (zooanthids and star polyps), both of which are doing fine. The bubble coral, however, has never fully opened like I saw it when I decided to purchase it. It has had some bubbles come up fully. I have moved it all over the tank. I've checked my levels, everything seems fine. I have 520 watt PC in 75 gallon tank. When it gets up closer to the light it won't come out at all, lower in the tank it begans to come out, but again.....NOT FULLY!!! Any suggestions?