I'll be plumbing my new 150 gal sps tank this weekend and would like to run my ideas past everyone. I've got an Amp Master 4700 that I'm hooking up as a closed loop that will be exiting out of a colum of four 1.5" bulkeads on either side of the tank back. A motorized ball valve will alternate the flow between the two sets every forty seconds or so. My thinking here is that the larger outlets will keep the exiting water velocity down to a reasonable level and yet maintain the movement of a large volume of water. The lowest bulkhead I was thinking of running into a 1" spraybar along the back, behind the rockwork, to aid in detritus removal. Let me know what you think. Twenty heads are better than one!