The Horticulture Lighting Group HLG 550 V2 R-Spec LED light will replace a single-ended 1000W HID while only drawing 480 watts at the wall and exuding the light output of 1,257 umol/s!
IMHO they are grossly overrating the HGL 550 V2 R Spec
Gavita says the 645w 1700e is good for a 4 x 4 area, and is 1700umol
HGL is 1/4 less umol vs the Gavita. 1257umol vs 1700umol
1000w Hortilux HPS is 1600umol Hortilux is 20% more umol, and is also rated for a 4 x 4.
HGL is a good light, but overrated for area covered. More like 3.4ft x 3.4ft
Gavita says LED should be 42.5w Sq/Ft using the very best Samsung/Osram Diodes