three 400watt hps lights in a series?

I just finished my first grow with one 400 watt hps light. I am starting construction on the new grow room soon, and was thinking of running a series of three 400 watt hps lights in a row. I plan on buying a large fan for the room, but I was wondering if my 125cfm in-line fan would be enough to cool all three lights if ducted in a series. Would a 6' x 4' grow area work well with three 400watt lights?

a 1kw would work better for a 6x4 than 3 400's.

i would say u want alot more cfm

http://www.businesslights.com/valueline-inch-435-cfm-centrifugal-inline-fan-p-2045.html
this one like 100 bucks with shipping and like 450 cfm
also i would do 2 600 instead of 400s 600 are more efficient and same watts as 3 400s