An older rule of thumb is that you need 30-50 watts per square foot. A 150W lamp really isn’t going to be effective coverage in a 2x4 IMO. I run 300 watts LED in a 2x4, and 200 in my 2x2.
Adding an HPS in addition to the LED would get you to a better light coverage, but utterly defeats the purpose of lowering temps…Those HID lamps are H-O-T!
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