Man oh man. I am in the stage of learning that in this cabnet you need to put into flower when she is about 6 to 7 inches.( I waited till she was 12 inches) And you need to LST her down. I think my main cola is going to not do to good. Do to being so close to my hps. But I would say that a 150 hps is going to be the best for this cabnet but a 250 gives you room to grow if after this grow you want to double you area and get the same cabnet that is twice the width and depth. On the fan i have a "desk fan" you know a 4 inch fan with the metal housing. It is working out great for me and it only cost 7 bucks.