Gold Hammer losing some color - help

[Reeferbadness]

I have 3 hammers next to one another in a 200g mixed reef tank. Both the gold hammers ( slightly different varieties ) have some discoloration in their polyps. The bi/color hammer next to them is fine. Any idea what might be causing this?

Parameteres:
DKH: 8.8
Calc: 460
Mag: 1420
Phos: 0.02
Nitrate: 10
Salinity: 34.8

 

[blaxsun]

I don't have any insight to offer, but it seems most prevalent on the third one. Any changes since you last posted?