My sps PE is greatest in the daylight and greatly reduced at night. Has always been that way.
My lps has always had the greatest PE at night.
I do not think that the role of polyps has been clearly defined in sps. I think that they may have alot more capabilities then given credit for. We see polyps snaring food in Lps and assume that it works the same for sps.
I know that when I increased the amount of white light that was on my sps, they increased PE. I also know that after a WC I have increased PE, I assume because of increased trace elements.
After several massive WCs the PE decreased. Possibly because of decrease in zooplankton or some other form of food. I refuse to believe that it was because of decreased nitrates.
My thinking is that the polyp plays a large part in the photosynthetic process (as opposed to just the skin of the coral); as well as food and mineral gathering and abosorbtion.
Clearly I am not a scientist. I am just trying to understand what I see happening in my tank.