I have never had sun coral, but I just read an article in Tropical Fish magazine about sun corals, and the author said it was a miss conception that suncorals need to be out of the light. The fact is that they don't need any light because they lack the photosynthetic zooxan-whats-its but brighter light did nothing to harm them. so you might as well put them in the light, where they probably get better circulation than the in some dark spot. just be ready to feed each polyp every day.