Coral not inflating during the day

[Parksy77]

Hey guys can anyone identify the cream coloured coral in my picture please, it's recently stopped enlarging during the day and I'm wondering if I'm doing something wrong

 

[Sniperhank]

I can barely see anything past the algae growth in the system. I would say that this is a major part of the problem. Algae growth can become invasive and strangle coral, along with the parameter issues that algae feeds off of aren't healthy for coral growth either.
I would suggest manual removal of as much of the algae as possible during large water changes with ro/di water.