Thanks for your help. I was wanting to go with another 600 watt because it is cheaper than buying a new 1000 watt setup plus I would be left with a 600 watt light just sitting there if I bought a new 1000 watt light. I guess I could sell the old 600 watt light to offset the higher price of the 1000 watt, but hell why go through all that when having 2 600 watt lights would give me more lumens anyway!