I saw a post on the now defunct overgrow.com, where a guy had a cabinet about the size of a C-22, and a 1000 watt HPS light. He decided to try the 1000 watt light in the cabinet, and it worked fine once he got his ventilation going good. 1000 watts is too much light for that amount of area, and he knew that, but he already had the light, and wanted to see if it was doable, and it was. So if 1000 watts is doable, obviously 600 watts is too. I don't think it will result in a major yield increase though, as the real benefit will come from the far ends of the area, where the 400 watt light might not be providing a lot of light.

A cheaper and more flexible alternative would be to put 4 30 watt CFLs at each end of the rectangle (where the coverage from the 400 watt light is at its weakest). This would provide 640 watts, but I think you'd get more light at the edges that way, and thus more yield. And you could turn off the CFLs but keep the 400 watt light running if heat became an issue, which is not an option when it's an all-or-nothing one-light situation.
jamstigator Reviewed by jamstigator on . 600W in a C-22??? A good friend grows in the model C-22 closets (2x4 ft) using 400W MH & HPS. Realizing that more wattage equals greater yields he wants to go to 600W systems all around. But, he says that he will not be able to control the heat. I say that he will be able to do so with proper cooling and venting. What do you guys think? Can a C-22 support a 600W system? What other factors must be considered? Rating: 5