I'm building my own grow cab. It's 32"w X 21"d X 58"h. I think that's about 28 cubic feet. I have a 25cfm fan blowing in at plant level and a 25 cfm fan blowing out the top. I'm thinking of getting a 400w hps/mh combo from Sunlight Sheds. It comes with an inline air cooled reflector and a 115cfm fan. Will I have heat issues. It seems like it's a lot of light for that space. My last grow was cfl, it was kind smoke but the plants didn't produce much. All ideas are helpful. I'm still in the building stage of my tent so a little design change would be easy.