Derasa pinching and discolored

[Grizzlyreef]

I have 2 derasas. One is 5" the other is around 8". The other day the smaller of the 2 moved itself into an area with shallower sand and fell on it's side. I righted it after about 36 hours and now the mantle is pinched and becoming pale in one area. Would the fresh water dip I read about work and what does it entail? Usually calcium is around 400, salinity 1.026, temp varies between 77F to 80F, Nitrates 20, ammonia 0.

 

[mbbuna]

how long have u had u had ur 5" Derasa. And What kind of lighting do u have it under.? (give us all of the details)

 

[Grizzlyreef]

I've had the little one about 14 months. The lighting is a Custom SeaLife PC hood, 10k and actinic (I'm at work so can't check but think they're 96 watts apiece).