If your ambient temps are really going to be in the 60's, you will have no problems whatsoever cooling a tent w/ a 400w using any cheap 4" fan and and filter. If you can swing it though, I'd definitely go 600w digi w/ 6" ventilation. Wish I had ambient temps like that.

have the same tent before i went to there 4x4 n added another 600! taking the 2-600's down n putting a 1000 in there place and then putting a 600 back in my 3x3 for a run or 2!! anyway, to the point! this was my set up and will be set back up the same way!! can filter 33 - xtrasun hood - active air 6in inline fan!! with ur outside temp would most deff go up to a 600 and feel thats a better light for that tent from my exp with the 6 n 4 in there!! w.wonka

@Vader: Thank you for the info. The 60 degree temps are a bitch because in the summer time it can get up to 90 so that's why I don't think I can use a 600w and buckets. But I think I might be able to keep a 400w with 6 inch ducting year round with some minor room insulation.

I also have opted to go with magnetic ballasts to keep price down for the first round. I gotta buy everything starting from scratch; meters, calibration fluid etc.... It all adds up when you don't have anything except a tent.

@Wonka: Thank you man, I really appreciate the pic and info. I will check into the recommended fan and filter. I think I can put off buying a filter until a little bit later maybe 2 week in flower at the latest.

Believe me I would love to put a 600 in there but I just cant justify the cost if its not gonna work all year round coupled with my current start up budget.