Dasaphrota, I have as of yet had no problem keeping sps alive and growing under p.c. light. I have a large turqouise acropora that is growing wonderfully, A piece of green acro that started as a tiny nub that is now 3 inchs high and has side branches all over it. I have a hydonophora that has done great for me so far, I have a bali slimer that started at 3 inchs and now is over 5 and has grown one good side branch and looks to be growing more. I have BT anemone that are now in a customers tank grown in pc light for 3 years now. I will say that the color on sps under mh is more brillant. However I have seen many tanks with metal halide that the person growing the coral could not keep it alive for anything. Now I do have a differnt P.C. light than most of the ones you see. It has 4x 96 watt vs the normal one that has 4x65 watt. I am of the opinion (my Opinion LOL) that the corals if given proper water conditions and cared for they want to live and will. I am watching my coral that I bought and fraged, as a brown ugly acro turn dark green, and am hoping for the little purple tips I saw when I held it close under a 20k MH bulb at the LFS. It is doing this under pc light. I am going to buy a 2x 250 wt mh with 2x 110 wt vho light system. Just because I want it. I grew sps corals in a 10 gal under 1x96 wt with a emperor 280 filter, and a prizam skimmer, with live rock and live sand. And that evil calupera racemosa. LOL. Just so you know I am very hard headed, and want to try to do thing people say you cant do, just to do it. LOL. I am getting better though. Hth in some way. Steve