marc, I have a 400mh and a 250hps they are perfect for that size room ...I go with harddon 3 plants full grown will fill that space, bigtime. the 400 w is rated to a 3x3
coverage area 9sf and I can keep my room at 85 max during this heatwave in the south...normally, I bypassed questions about heat control, because my room is ac'd,
but the ac is on the fritz 110 degrees heat index...records yesterday and today in my region...and I am running both as well as 2 45w cfl's so your looking good, man.