I have 2x 250w Mogul MH fixtures with spiderlight reflectors positioned about 9-10 inches from the waters surface on a 48x24x30 (150g tall) tank. Currently I am seeing growth on my montis that are high up on the rock work, about 12" from the surface and on my lps and softies on the sandbed. If I wanted to place a clam on the sandbed, or even just generally improve the available light in the tank, should I replace the spiderlight reflectors with Lumen Brights or another similar pendant style? I'm not wanting to grow SPS on the sandbed but I want enough light for possibly a clam, or at the very least, my plate, acan, lobo, and zoas to have good growth. Any suggestions from others with deep tanks is greatly appreciated.

If necessary for a clear answer, I am using 2 magenta/4??nm blue 48" ecoxotic stunners with reflectors for supplemental light and nothing else.