I have no idea how much LR, but it's about 20 lbs. less now. My philosophy is minimal rock touching the bottom, so I use as much Tonga branch as possible and build off of that. Now everything is just "floating" and I get better circulation throughout. I think you can get by with less if you have good circulation. When I took it all apart yesterday, there really wasn't too much detritus for the ~2 years+ the tank's been setup. However, I do siphon it weekly into a 100 micron sock.
Oh, and Rev, I don't even recognize some of my own corals! Your macro shots are amazing! Must be that fancy lens.
Dave