Well just to add my 2 cent. I have a GC 180 with 2X 250 MH in luminarc reflectors. I keep everything form softies to SPS with no problems. With that being said my rock work is set up in two pillers or mounds and the lights are centered abouve those rock structors. I have bee considering getting a third MH but only as a sumlementation to the XM 10K bulbs that I am running in the 2 that I have now. Hope this helps!