Any good reef supply store. There are still more VHO lit reef tanks than LED tanks, if you can believe suppliers like PA, and the like - they ship bulbs like crazy. The people online do not represent a critical mass of everybody in the hobby - and most noobies have never heard about VHO, but would sometimes be better suited with them. The VHO bulbs last for 2 years, have twice the output of T5 (at twice the wattage, so it is a push). I just got 2 brand new IceCap VHO ballasts and harnesses and I had to pry them from the hands of the people who had them. MarineDepot, Premium Aquatics and the like sell out of the bulbs faster than UVL can make them. They are a great reef light that was out-hyped by T5 and LED, but perform better than either IMO. The size of the bulb also makes them harder to put into fixtures, but I would pay good money for a HQI and VHO fixture if AquaMedic, or the like, would make them.