Stylo bleaching

[Deve]

I've had a healthy Stylo colony for over a year and have noticed the branches in the middle have just turned white within a day. Approximately 20%. Alk is 8.3 and calcium is 480. No major changes to the tank. Should I frag the rest of the colony in the hope it doesn't spread? Dip the colony? Suggestions?
Thanks

 

[vetteguy53081]

To determine the best recourse:

Did you add a little alk which is currently a tad low?
Is it getting full light or partially shaded ?
VERIFY Salinity as high salinity will cause this.
If all checks good, yes consider fragging those pieces.