Some brittle branches, crush to sand between fingers

[Bongo Shrimp]

So I noticed today on my biggest healthiest acro colony, a few tips had died or were dying, nothing rapid. So I went to cut them off cause this acro gets bumped sometimes by me working and it just regrows super fast. But when I cut the tips, I didn't even cut, they almost just fell off when I touched them and they were so brittle that they crushed to like sand between my fingers. I check a few other branches that were visually healthy and some were super brittle, some rock solid. I have had this acro for over a year and a half and it has grown from 2" to 7" in diameter. Any idea what this could be?

Parameters:
pH: 8.1
Alk: 8.3 dKH
Cal: 400
Ammonia: 0
Nitrite: 0
Nitrate: 0
PO4: <0.05 (salifert)
Mag: 1350

 

[Acronic]

its due to an imbalance. typical culprit is between mag and cal.

The aragonite polymorph is taking a back seat to the calcite polymorph during the calcification process.

Its nothing to worry about. Try adjusting your cal or mag levels :thumbsup:

 

[sahin]

Your parameters currently appear fine. As Kevin says it could have been caused by parameter imbalance if they were "out" of range previously.

The other thing that comes to my mind is water flow. Makes a BIG difference in my experience.

I run my Mp10's at constant flow (around 80%) all the time. So the corals such as millis near the middle are getting smashed with flow ALL the time. These are ROCK hard and I find it so difficult to cut them. Tried snapping with tweezers...NO CHANCE. Tried cutting with bone cutters...still struggled.

However, other pieces in softer, indirect flow I can snap branches easily with tweezers. I can even crush the growing tips into a paste with my fingers...

Just my experience.