thanks guys.. I've got a 55gal holding tank in the garage so water's not the issue..
Lastnight, I saw a little water coming out from under the sump pad (the entire bottom of the cabinet has a 1/2" foam pad to help with resonating noise). I couldn't figure out why the water was there (checked all drain and return piping, all bulkheads, all "wet" exterior equipment like UV & Chiller but I couldnt find any reason for water to be under the pad). I removed the refugium from the equation so I could have more clearance to check everything out again, but I couldn't find anything. Refugium is sitting in the garage now.. The only thing that I could come up with was that there must be a slow dripping crack in the sump (Raj will like this because it pushes me to have him build a sump for me). I put everything back together with the exception of the 'fuge and when I did, I inadvertently knocked the "chiller return" hose out of the sump. It fell out of the sump and proceeded to empty the sump into the base cabinet. about 5 minutes later when I was crawling into bed I asked "what's that noise" (we've got a pretty noisy house with baby monitor and fans). I opened up the base cabinet and it took me a minute to actually figure out what I was looking at.. There was 2" of standing water in the base cabinet and the sump was empty, of course, the sound I heard was the return pump gurgling for water.
got 99% of the water out quickly with towels and a bucket, but it had already started to drain through the base cabinet onto the carpet (side note, REALLY glad I didn't put hardwood floors in the office before I built the aquarium).
so that's where I am now.. cleaning up water from the carpet (my shop vac is at my fathers house because we've been finishing up his basement) with towels and a "please don't leak again" dance.
I think the sump still has a crack in it so I'll be calling Raj this morning.