That white bottom is `starboard' ... very similar to cutting board material, but the stuff he's using is actually from boating-uses.
The thread detailing this setup [and eventually a number of places to get this material, other folks who used it in different colors] ... is at:
http://reefcentral.com/forums/showthread.php?s=&threadid=223301&highlight=starboard
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And Gregt is dead on with the skimmer - BB's main requirement is getting the detritus/etc out of the tank ASAP.
Unlike a DSB, which is `sinking' and storing the detritus, poop, food residue, phosphates ... BB is base on a high-flow, detritus-suspension, wet-skimming removal of all such products from the tank as quick as possible.
This quickly removes all phoshphates from the system ... and will get other compounds gone before they have a chance to break down [instead of dealing with nitrate reduction, this removes things before they have a chance to break down and cause nitrates ... or at worst while they're in the process of such].
Key to this all is the big, efficient skimmer ... as it's the main `removal' technique for all this crud. I find dumping my skimmer cup in my toilet is the best method for `processing' phosphates and nitrates ... far better than leaving them in the tank [for algae/etc to go to work on].