I use 6500k 4' shop lights on my 4' long tanks. you could checkjout home depot/lowes.
see: Lithonia Lighting 2-Light White T12 Fluorescent Shoplight-1233 SHOPLIGHT at The Home Depot
and
Commercial Electric Basic 2-Lamp Hanging Fluorescent White ShopLight-CESL401-06 at The Home Depot
I believe the second one has an electronic ballast. FWIW
my .02