I also have the Hex II. Hex makes a terrific, solid unit but he never kept up with the technology.160 watt
lamps are not made to function well on the electronic ballasts because it is spliting the power to 2
lamps and under powering them, unlike the choke ballasts that drive one at a time.You can not hook a transformer to the unit.The best lamp that I have found that works for me is the Wolff solarium XLR 160. They are usually expensive though because I can not find them many places.