I have a 75 gallon reef tank that I would like to get 2 PFO pendants for. My question is about the cost difference between running two 400W bulbs vs two 250W bulbs. I also would like to know if 250W is enough to effectively keep and grow SPS's. Oh and the 2 PFO pendants I would like to get also have 2 28W power compacts each so those would be actinic while the MH would be a 10k probably. There isn't much of a price difference on the dual ballasts or the bulbs, but I was wondering long term if the extra power consumption is worth it. Does it actually make coral grow faster/better or is 400W halides just too much on a tank of that size. Oh and I don't have a chiller, but the tank and sump are in the basement and the light will just be hanging from the ceiling, not enclosed in a canopy.