Can i use a fluorescent to add extra light while using a high pressure sodium?

I have a 600 watt high pressure sodium light and recently added a 4 foot double tube standard fluorescent grow light to the areas receiving less light. I had the fluorescent on the floor under the plants, but recently hung it about 1 foot above the plants.

My question is two fold. first, is it better to use suplemental light on the floor or hang it. Second, should I be using a combination of the two or will that mess the grow cycle up (currently 2 weeks into 12/12 cycle and seeing 3 inch buds and full plants)
 
Top