Yep! Plus, some people end up with "Zip" cuzz they haven't got a friggin' clue! A 400 watt HID doesn't produce buds, a grower does! A grower's experience is the "Sharpest knife in the drawer"!A generic rule of thumb is 1 gram per watt, if ya know what you are doin. Some say they achieve a little more, however, I think most people probably get around half a gram per watt.