Well I guess I'll reply to this - even though I'm going against the norm, and will probably get ganged up on for stating this.
I have a Rio2100 on my 55 reef.
I've heard some of the horror stories from others on this board regarding Rio's, but so far to date I have experienced nothing unusual with mine.
I also turn mine off when feeding. On my 55 gallon tank, much of the food is lost to the overflow and prefilter if I let the return pump run at feedings - so I shut it off.
I do this once a day, and have done so for the last year with no complications.
As you've probably noticed crablegs, when you're cleaning the pump, there's really not much to these pumps. A motor housing and an impeller assembly is the working parts of most pumps. If you notice some build up of gunk, clean the shaft and housing with a small brush.
You will not "hurt" the pump by turning it off and on, but as Mr. Salty mentioned, if you do happen to have one that was not manufactured correctly, or is defective, you may experience a lock up.
In my opinion - it would better to force this lock up to occur by performing a daily on/off routine, than to blindly assume it is running fine, only to have it lock up on a power loss when you were not around.
Only my opinion -
By the way LOL - I recently purchased another brand of pump for my 55 tank/sump.
Usually there is much truth to these horror stories, and I'd rather be safe than sorry