Generally, the rule is 3.5 watts per gallon, whether it be VHO, PC's or MH to keep majority of the softies. Clams and few others that really need a higher intensity, can get by with them as well but they need to be placed at a higher level in the tank so that the mantel and the corals can absorbe the light. Stoney corals need around 5.5 watts per gallon and with that you can house nearly them all other than carnations that need no or low light. simply place those underneath a dark crevice. Adding softies and SPS/LPS sometimes causes a "coral war" in the tank due to the fact that most softies are little more potent to the average lps/sps except to like firecoral or galaxia which have a powerfull sting even to humans. Softies, like other corals send out pheremones in the water. Other corals smell it and go into DEFENSE and start whipping out stinging tentacles that wipe out other corals around. you can generally see it in the daytime with maze brains and the like. Back onto subject, 3.5 watter per gallon to 4 will do just fine.
