I can point to this first. Sps do not like any high levels of phosphate or organics. You have too high of a bioload in your tank and it doesn't matter that you have a tank full of liverock. You have a ton of fish, they have to eat, they have to crap and that all ends up one way or another in phosphates and organics in the system. I bet you would be shocked at all the waste down under and in between the rock if you could take all the liverock out and some how shake out all the waste. Following are a few negative effects of high organics in a tank.
Not only can organics be taken up directly to provide carbon, nitrogen, and phosphorus, but it can be broken down by organisms and released as inorganic nutrients, such as orthophosphate, ammonia, nitrite, and nitrate.
The consequence of this oxygen consumption is that oxygen levels may be lower in aquaria with high organic levels, especially at night when photosynthesis is not producing excess oxygen. Moreover, during a power failure when both aeration and photosynthesis are greatly reduced, the metabolism of organics proceeds merrily along, reducing the oxygen content of the water faster than it would in the absence of dissolved organic material.
A lot of soft corals fair a lot better in such systems but sps need a lot cleaner systems to survive. And you also realize that on a sps reef in the ocean there are hardly any soft corals and vice versus. They really do not like each other a lot. And the sps could be dieing as a result of chemicals being put off by one or more of your soft corals. Are you running any carbon? How often are you doing water changes? You must have a huge skimmer, is it putting out a lot od skimmate every day? If not with a bioload like you have it should be.
