What In The World

[Foxchase]

I've slowly been losing Hammer heads this same way and i have no idea why. They shrink up over the span of a week or so and just slowly waste away. Went from a 60+ head colony to about 7 heads left. 3 of which are now looking the same.

Any tips? Help? Ideas? Anything? I have framers and frogspawn that look perfect and continue to split.

 

[Foxchase]

General info:
Tank is a 40B with a 20 sump. 2 ai Primes 16HD. 2 years old
Nitrates: 12
Phosphates: .06
Alk: 9.0
Calc: 430
Mag: 1400
SG: 1.024