Well I sit corrected, just goes to show that almost anything can happen in a reef these day's
Ed,
As for feeding, I drop my food directly ontop of a 402 powerhead so this blast food through the entire water column, allowing all fish and other critters to feed together. The gobbies will actually feed alot of the time before the food even hits the sand. They are just like the rest of the fish when it comes to feeding I guess- hungry!
With your 130lbs of live rock you should have lots of healthy goodie's living in there. Your sandbed will also serve as a major home for critters too. As long as your reef is somewhat established I see no problems there. I have never ordered critter packs, instead I have traded a few scoops of my sand with a buddie's 20gl refugium sand once or twice a year. My watchmens and my six-line tend to keep things under control in that department now, however I don't think that they would be able to wipe out my entire healthy stock of such critters.
Hope that helps
cheers, Rich