co2 is the key to get 1.5g per watt...... i have many harvest on my belt and have been growing for years, ive used 1000w before and im currently using 8, 600w lights with sentinel co2 ppm reader and a co2 generator produces the co2, i use 4800w total, and cover a 14x10x13h i average 1.1-1.5 per...