dying torch

[Perureef]

I'm having a issue with my torch coral. i had him for 3 months now with no issue, but now within the past few days one head has died off. there are some factors that might have lead to this. first of all the coral is placed at an angle, and the head that died was the one that was most shaded. can heavy shading cause this? also, most of the coral is in general at an off angle from the light (4*54W T-5's ). the current is not crazy strong but is strong overall relative to other locations. finally, in the past few days my Ca levels have been low as i waited on a pH probe for my Ca reactor (360 ppm), would this have an effect. the heads more proximal to the dead one have not expanded, while those more distal stil have more expansion. should i remove the head? what can i/should i do? should i move it? any advice would be greatly appreciated.

ammonia: 0
nitrite: 0
nitrate: 0
pH: 8.13 (6 pm)
Ca: 360 ppm
Alk: 8.0 dKH
salinity: 1.024