these single mouth sun corals are actually easier to care for vs. normal sun corals cause there is only 1 mouth to feed haha and it is always open for feeding.
they have a tendency to open its tentacles 24/7 without regard to lights. Normal suns in my experience would slowly close it tentacles when lights are switch on (of course u can train it to open at specific times thru your routine feeding schedule)
i believe normal sun close their tentacles when the lights are on are usually due to the floating swimming mirco pods, plankton disappears when lights are on. I may be wrong,it is just my observation.
Another theory i read was due to the rinising temperature in the water column.
what ever it is these corals like the normal sun do not need lights to survive they need food.