My father in law owns an electrical supply co. The put new lights in a building and he gave me the old 3 tube fixtures the took out. My shop is 24 x 24 and it has 60 4ft tubes in it. I have to wear sunglasses to work in it. LOL
My work shop has low bay sodium lights that are the best lights I have ever seen. I have 4 lights in a 30 x 50 and it is perfect.