Is my light killing my tank!?

So I got a 48" AquaticLife T5 HO light with 2 54W Actinic and 2 54W 10,000K bulbs back in May. My tank went through a huge algae bloom immediately after I added the light. My live rocks were looking very good prior to the light with lots of different coraline algaes all over one and spreading to other rocks. After the algae bloom a lot of the coraline algae died and it still looks like its not rebounding.
The first picture shows what my once covered rock looks like.. the bleaching seems to be growing.
The second picture I just put in here to show what it looks like on the bottom side of the same rock. Notice the dark blue/blackish hue.. is that normal?
The third pitcure is of my live sand. Bubbles will form within the sand when the blue light (actinic) is on for a prolonged period (1-2 days). Is that normal?

 

Was this a newly cycled tank?

If so the coralline will grow back. Not uncommon for coralline to die back in a new system that has just gone through a cycle and not uncommon to see changes in coralline color and growth when you add a new lighting system.

Make sure your parameters are in check with regard to ca, alk and mag if you have not done so already.

Yes formation of bubbles in the sandbed is normal.

 

What is your light period for blues and daylights.

10-12 hours should be the max for blues, 8-10 for daylights.

 

The bubbles are nitrogen from the breakdown of nitrates. A normal process. It seems to be more active when the lights are on.

 

Corailline:
good news to hear about the bubbles. Don't have a way to check my calcium or magnesium but my alk shows to be ideal. nitrates and nitrites are down and safe as well. This is not a new tank, I've had it for 5 years now. The salt I use is Instant Ocean Reef Crystals so I figured the extra trace elements and calcium would suffice

 

2in10:
10,000K(White)= 8 hrs
Actinic(Blue)= 12hrs