I dont know where you're going to find 50-watt fluorescent tubes ... no such thing, as far as I know ... 4-footers are commonly 40 watts, and eight-footers are 80 watts ... GE Cool Whites provide your 'blue' spectrum for vegging, and GE Kitchen & Bath are 'red' spectrum, for flowering ... find them at WalMart for about $7 a pair ... :smokin: