While they are not metal halides they are PC and yes they are carry over from a reeftank projects, I have a 55w and a 36 watt sitting 2 feet over a set of tanks that has gotten in credible growth, even the moss seems to be taking over double time. I prefer these spectrem since the give really good looking spectrum without producing too much UV. In fact some of the "growlights" can be more harm to plants than the higher kelvin ratings because they produce quite a lot of infared lighting. Ican post some pictures soon.
Danny