You are so modestLindsay, being no expert at this I would say that is Diodogornia nudilifera due to the colours and contrasting calyces. If it is it is aposymbiotic and then lighting is irrelevant, as they have no zooxanthellea. Not the end of the world though. They feed on zooplankton and phytoplankton. I feed mine the following and they seem to be doing well. I use a mixute of Cyclopeeze, Coral Frenzy,and a combination the following Kent marine products ( Phytomax,Zoomax+ Chromomax). I feed twice a week and mine are doing just fine. Be careful to watch that algae does not grow on them due to the light. But nothing a light brush can't solve. This mix is good for your other corals as well so no wastage. The Kent product is highly concentrated and I only use 1 drop of each per feeding.