nicest coral turns ugly?

So i bought a nepthea tree about 4 months ago it was small! And it has tripled in size since and was massive! But i upgraded my lights too leds and he seemed too really liked it, he was fine for about 1.5 weeks and then he slumped over and turned really stiff. since that he was slowly losing color i had no idea what too do but too move him lower. so after he was slumped over for like 2 days he then had this brownish coat over him. i did research and found out he was shedding. thats great but why would shedding make him lose color? ever since he still is not nearly as close to the size he used too be. i dont think its the light. what could it be? will he get his color back?

 

were there any other changes in the tank besides the lights? I'm not an LED user but I know people talk about them being run at lower percentages and then slowly ramping up color....did you start out low?

 

No other changes, I did add chemical pure.... And yes i acclimated

 

I have corals in my tank that don't like chemipure at all. I'll never use it again. I run purigen and couldn't be happier.

 

A picture of the coral will help. I used Chemipure for years on my reef systems never had an issue (make sure its rinsed properly).