Thanks everyone, and keep posting if you other thoughts.

Matt - nice typo on my part. Daily temp range is 82 - 86. More in line with the Caribbean than Indo-Pacific, but that's a tired old thread I don't want to start up again here. In the new system, I'll be doing something like this to stabilize the daily swing:
http://reefcentral.com/forums/showth...erature+sensor
But I'm off topic already. Bottom line is temp is good. I like your advice on the pump swap, and I'll start thinking about whether I can pull this off. Also, I see what you're asking on the half-full question. I'm bypassing most of the sump volume right now (not having to fill it with water), and I built my OF box on a sliding track, so I make up for the remaining 6 inches of missing water in the display tank by lowering the inside and outside boxes and using really long temporary u-tubes.

Josh and Matt - I think I'm gonna follow your advice (as well as Randy Holmes-Farley's) and put in some of my 75g livesand and try to get some of the organic ooze to help me out.

Vinh - You're probably the best person to comment on frequent new setups ;) so I appreciate your advice as well. I had probably 1/2 inch (which rounds out to 2.5 gallons with my tank's footprint) of city water in left in the 150 when I began mixing new SW. The kalk was considerable, and I considered draining & starting over, but the Ca and pH and alk are totally normal, so it had me stumped.

And it's been five days!

Anyway, I think your suggestions are gonna be productive; I'll keep you posted.

Dean