Sweet deal on the setup. I would just change out 3 bulbs into the 6.5K to 10K range and let the other 2 be the 18K bulbs because it will be considerly cheaper than going SW Reef. The bulbs should be less than $60 and the reef you will have $200-$300 in just a skimmer and NO bulbs wont work for a reef so you would have to change out your entire lighting setup plus filtration, flow, substrate, LR and PH's