Well this is the second time this is happened to me, and now I am well aware of all the clues... so I hope the following helps some people:
I've been pretty busy the last couple weeks with work, the new server etc.. however I did pause for a moment a week or so ago and noted that my tank was a couple degrees hotter than it usually is.
I didn't have much time to think about it, but I was starting to notice other things in the last few days... my chromis was acting funny.. the return of this dental floss algae that I thought was receding and a couple spots on my angel.
Now I don't know if I can attribute it all to just one thing.. but it all added up to something is askew. [smiley=stop.gif]
So I had a look under the hood.
(One drawback to having an auto top off system is you are not looking at the sump everyday.)
Sure enough I noticed that my Remora skimmer wasn't running. Since I recently started dosing kalk again I wasn't all that surprised but I was kicking myself for not adding all this up sooner. I am not sure how long it has been out of commission.
So I unplugged the maxi-jet and pulled it out. It was hot to the touch. JAMMED. >

That settled the temp mystery right away.
I pulled it out and brought it to the sink. When I pulled it apart a big cake of kalk came out. I cleaned it and of course, being a blockhead, put it back on the skimmer without testing it first in a bucket. Of course it wouldn't start.

So back into the sink and in a bucket it went where I finagled it to life.
Now all is well and I can relax for a while.. tomorrow I will do a water change for good measure.
HOPE THIS HELPS... Check your pumps!
matt