You have to feed the sun coral. It doesn't need light, it needs food. For what you are keeping, you can upgrade, but I do not feel it's necessary. I do feel for your tank, either t-5 or VHO would be nice and expand what you can keep. If zoos won't open, look into your water quality. Do you use RO/DI? Salt used? Skimmer? Water parameters (nitrate, phosphate, temp, pH, SG, calcium, alk and magnesium.)
btw, I would consider VHO's. 4 bulbs. 2 50/50, 2 actinic bule. Nice combo. This would also be my opinion and others may disagree with that. Personal tastes.