Depth and MH Bulbs

[DLANDINO]

I am curious about the suggested depth of light penetration, MH bulbs and SPS coral. Most bulbs in the 150 watt range say that they are good for reef tanks that are up to 22 inches deep. Does this mean that SPS coral can thrive at the lowest part of the reef near the sand bed? Currently I have all of my SPS on the top tier, LPS middle and lower. I am looking to expand my SPS and am running out of top tier real estate. Thanks.

Dave