Chalice help needed!!

[onelow64]

I've had a chalice in my tank for quite a while and last night it has a white deterioration on one of its sides. Any help is appreciated. It's roughly 7 inches x 4 inches and the spot is about the size of half a dime.

Last night ...



This morning ...



39 Gallon Solara
50 lb rock
Chalice
Hammer
Misc Mushrooms (roughly 12)
Tera trees (4)
Torch
Candy Cane
Star polyp frag
Brain frag
Zoa colony
1 fire shrimp
6 blue hermits
6 nas snails
1 six line
1 bicolor blenny
1 clarki clown

 

[KJ]

Can you post your levels KH MG CA ?

 

[onelow64]

KH 11.8 dkh 4.2 meq/L
Ca 440 - 460
Mg 1120 - 1160
PH 8.0 - 8.2
NO3 2 ppm

Those are all of the kits I have.
KH, Ca, Mg done with reef foundation pro kit
NO3 Salifert kit
pH sera kit

 

[onelow64]

Mg seems low to me. I dose every two weeks with Seachem reef advantage magnesium. Should I do it every week?

 

[The Kahnasaur]

Since you have a high dKH, your Mag is pretty low. I'd try to raise Mag or lower dKH. Chalices can been finicky though so I'd alter things slowly.

 

[evolved]

Agree with the chemistry comments. What other corals are near that edge? May have possibly been stung.

 

[onelow64]

No other corals are around that side of it.