I do my spot feeding about 1 hour after lights out as I have a candy cane and a trumpet which feed in the dark they have little tenticals they extend after dark for feeding. My self I do not turn off my power heads but I do know people that do and thier carals may grow a bit faster than mine. The way I see it in the wild the ocean does not spot moving so I don't stop mine either.

Ultra Min s and Ultra Organic should be ok it is just a preferance as to what product you use. I spot feed zoo plankton and rotifers the rest of the food and nutrence the corals get for what is in the tank already and left over food from feeding.

Bill