View Full Version : 400w vs 600w

05-14-2010, 01:25 AM
I'm getting the growlab 120 & was wondering what light will produce the best yields. I was thinking the 600 cuz hey more is better right? but I did sum research & found with 2 feet of distance between ur light & the canopy u divide the # of lumens by 4. So if u do the math u come to find out that a 600w hps at 18" away will actually only deliver 300w to ur canopy. While a 400w at 12" away will deliver more than 300w to ur canopy. I also was concerned with cooling the 600 would that be an issue?

anyone with info on wut I should use?

11-13-2010, 05:54 PM
For that size a 600w would be good and also always keep the light 2 inch above the top of plants for max use

01-11-2011, 10:41 PM
Yeah, bigger is better so long as you have room to accomodate plant growth. I'd go with the 600 if you have room.