600W lights are also the most efficient.

1000W puts out ~ 140,000 lumens
600W puts out ~ 90,000 lumens
400W puts out ~ 50,000 lumens

That's from my head so the numbers might not be 100% correct but they should be close. :jointsmile:
canuck grower Reviewed by canuck grower on . 2'x8' whats the most light i can rock ive got a 2x8 area thats 16 sq ft im thinking 5 180cfm cfm fans exausting to the attic 3 400 watt hps is that to much / will it bleach my plants and is that enuff cooling / ventilation for 3 400watt lights Rating: 5