probably both the density and yield would be better with the larger light. im not sure about cost, since you would have to figure in the costs of keeping the temps down, more fans ect. i wouldnt think 400w would be to expensive to run, but i havnt got mine yet. i only have 150w for now. the bill isnt noticibly different, 5 to 10 dollars a month more than without. so guessing 20 to 30 a month depending on if youre vegging or flowering.
twoguysupnorth Reviewed by twoguysupnorth on . Just starting to grow and need some help Hey :) We just joined this site because we have been moving around a lot and finally found somewhere stable to live. After growing outside and not being too successful, we are now trying to move to hydro. We want to grow anywhere between 4 and 6 plants at two feet tall. We wanted to know if a 250 hps or 400 hps would be needed. We kind of want to keep the electricity low but also want to maximize plant potential. Also we wanted to know if a 5-10-5 solution would be a good root stimulator. Rating: 5