Im looking for a t5 setup that will fit in a canopy of a 75 gallon. only have about 15" max width...would like the most bulbs as possible....i dont know if six bulbs will fit with all the websites stating different sizes for the same retro's and fixtures. Hate to buy and it wont fit. My tank has the offset megaflow over flow in the back. Cant remember waht tank brand that is.