LPS issues

[Cameron]

pH very low...how can I raise it?

[zazzoo]

ph buffer..... the powder stuff.... raise it slowly ... check ur hardness too that also plays a big part

[Cameron]

pic

[zazzoo]

once something like that happens... its almost to late... but u can still try

[SeaHorse_Fanatic]

Looks nibbled on.

[Whatigot]

definitely looks like an lps eater has been at it...
IF your params are all normal, i would look at the affected corals at night time to see if anything is eating it.

[mseepman]

I agree, that looks like it was an entree for something. I believe some people use a red light in their efforts to watch stuff at night without scaring it off right away.