HELP, back from vacation and SPS are bleaching rapidly

[LivinTheSwreefLife]

I just returned from a 10 day vacation, during which I had someone coming by to feed the fish every 2-3 days (I pre-measured food so there should not have been an overfeeding issue while I was gone). When I got back, 4 of my SPS frags were bleaching at either the base or the tips, with about half of each frag damaged/tissue gone. As of this morning, another SPS frag, which was fine last night, is half bleached/gone. The other 7 SPS frags are fine, and the 2 LPS frags/colonies are fine.

I checked all the lights, ATO, pumps and other equipment and all seems fine.

Here are the measurements as of this morning, with my usual parameters/targets in parentheses following:
Temp: 77 degrees (same as usual)
SG: 1.024 (usually 1.0245 or 1.025)
Calcium: 425 (same as when I left, usually closer to 450 though)
Alkalinity: 8.5 (usually between 8.6 and 8.9, but I've had larger swings than this with no issue)
Phosphates: 0 (same)
Nitrates: 0.2 (same)
Magnesium: 1320 (same)

So far I have not done any water change because my RO/DI unit adapter isn't working properly and I can't get the connection to the sink to work (when I do get it working I can only make a small amount of water, perhaps a gallon in 3 hours, because I have to keep the water pressure low to keep the adapter from breaking. I ordered a new one but that doesn't help me right now). I do not run carbon or GFO or anything, and have not added anything other than 2-part Calcium/Alk additive, and I don't run a skimmer.

Anyone have any ideas on what could have caused this or suggestions for damage control?? I will also do a water change as soon as I can mix more water.

:( thanks

 

[twilliard]

I am thinking something may have been introduced in the water while you were away
I have seen this to be common when some one else takes care of it.

 

[143MPCo]

..find yourself a LFS that sells RO/DI (normally like $.25 a gallon) and make up some saltwater, if that's not possible distilled water will also work in a pinch... you'll also want to add a bag GAC in a highflow area to try and remove any toxins that MIGHT be present.

 

[larangcon]

Long vacation and SPS doesn't go well as i have been there recently. Small water changes should get you back on track, mine took a month to recover.

 

[LivinTheSwreefLife]

Thank you all for the replies. I will get some RODI water and carbon on my way home tonight and do a water change.