Bubble Tip Problems

[CandyCane]

So since I got my RBA in august
- it has gone from a rich orange colour with a green base
- then to a florecent red with a white base
- It also went from being happy at the top of my tank where there was flow and lots of light
- now underneith a pile of rocks on the bottom of the tank where there is no light and probably very little flow.
-it never has bubbles and barely any tenticles to speak of
-its stalk is healthy and its able to move quickly around the rocks and attach very well

I'm very concerned with whats going on and I would apreciate any tips as to what could have caused these changes and how I can caux him back into what he was.

Water parimeters:
specific gravity- 0.0252
Ammonia- 0ppm
nitrite- 0ppm
nitrate- very trace amounts

I dose the tank with:
Strontium
Iodide
liquid calcium
magnesium ions
Fuel
directly feed corals with chromaplex and coral accel

I do RO water top offs in the morning and at night to keep salt levels in check