MonKei

On checking out my tank yesterday evening, i was looking at the zoanthids... I noticed the green guys looked like they've been munched on or are wilting and the red/brown ones had a white patch on them..
Top arrow points to the "dull looking" one, right arrow points at the "injured" one

white patches on the polyps


(sorry for the mediocre photos, was using my phone cam)

I did a 10% water change yesterday afternoon, and checked my params ~noon today, 0ammonia, 0 nitrite, no detectable nitrate... PH was a bit low somewhere between 7.8 and 8.0, but I checked before my lights kicked on, so the ph will most likely rise a bit over the day...

Any thoughts?

(on a side note, i checked my source RO water -- which is from my unit at home -- 0 am/nitrate/ite, 7.0 ph, just for kicks)