Whats wrong with my zoas?

[nanomania]

Suddenly my zoa, especially this colony is melting.

Cal 450
Mag 1250
Alk 7.1
Po4 0.02
No3 10-12

500mg vitaC dosing 2ice a week since 6 months

 

[Best Fish-Jake]

How stable is your Alk? Zoas don't take too kindly to swings..

 

[nanomania]

How stable is your Alk? Zoas don't take too kindly to swings..

Pretty much stable, had gone to 6.8 after adding sps

 

[Labridaedicted]

have you tried dipping them to rule out parasites/predators? Any peppermint shrimp? Mine used to pick at my zoas and they would often be partially closed like this due to that

 

[wattson]

Do you run GAC in a reactor on your tank ?