Mixing lights??

I am planning on buying one of those PC planters... Sunlight Sheds Hydroponics Systems

I realize that one 50 watt HPS is not enough light for a successful grow. I am considering putting an additional flourescent light in there along with the HPS, would this work? Also, do u think the PC planter would work in general?

light should be dependent on 2 factors. square footage of the grow area and lumens per square foot. measure ur grow space and use these parameters min 3000 lumens per sq foot. med 5500 lumens per sq foot optimum 10,000 lmns per sq foot. holp that helps u out