is the return in wieght comparable to the extra cost in electricity!??
i run three four hundreds in a two meter square room. and two six hundreds in another,there is hardly any diference even though the two six hundreds give out more lumens,,,,,just wondered, haw big, and how many plants ya have under all that hps?,,wouldnt it be better to have room for the lamps to be raised insted of tieing back all the time!,
interessting grow set up!,,,,seems to ring abit of " mines got more watts than yours, even if the weed does cost a fortune to grow!,its better!."syndrome.
anyway hope it pays off for you, or you dont pay the bills!, lol
last coment,,, i use multiple cool tubes [150 mm ]conected to a 200 mmm carbon filter and inline rvk extractor, the filter sits in a box where the tubes from the cool tubes conect, this allows one fan to run two lamps without loss of cooling, however you do need to fit a paper filter to the end of the cool tube, or it gets very dirty, very quickly. by extracting all the air from the grow room threw the lights, filter, and out the room, i can maintain the heat within the room, for wich i have AC, the fresh air is drawn into the grow room by vacume!,, if i draw out 1200 meters cube an hr, thats the amount of air that will be drawn into the grow room! thanks to the aircon that will be at 18 to 19 degrees
the temperature at the leaves with the lamp 30 cms[one foot] above is 22 degrees, the cool tubes do get hot! but only within a few inches of the tubes! if your tubes are this low, the spread of light will be minimal!, if all tubes are in one! cool tube then they canot be adjusted to compensate!, you maybe, would have been better with a light rail and two 600's ??
definately more economical!
good luck with your grow,
and burn a big one !