200 lbs of live rock in a 55? Sounds like you need to have a sale. I'm amazed you can fit all that rock in there and still have room for water! Live rock will certainly help with filtration, but only up to a point. Since there are all sorts of thngs living on the rock, it also presents a bioload to the tank. Plus, with that much rock, there's almost no way you can get decent flow in and around it all. Try taking half of it out, and I'm assuming you have a sand bed, get the rock up off the sand and off the back glass so you can get some real flow in there. You can use PVC tubing, cut into rings, to get most of the rock out of the sand, then just bury the PVC in sand.

If you have no sand bed, which some people like but not me, you can have more rock in there, but you're more dependent on aggressive skimming and macroalgae for filtration.

edit: oh yeah, I almost forgot. "Cooking" the live rock, I assume in order to sterilize it, is a really bad idea. You'll essentially be introducing huge amounts of dead stuff into your system. Forget you ever heard this extremely questionable idea, no matter where it came from. You pay $5/lb for rock that has marine life on it and then kill all the life? Come on....