My calculations on the 600 were as follows:
Yes 1000 W is greater than 600. But the 600 can be placed roughly 12 inches closer to the plants which.
Light output divided by ditance squared = lumens
1000 watts/3x3=9=111 lumens
600 watts/2x2=4=150 lumens
and some other stuff I read..but thanks for the claifictaion godess
just additional things i read....
"Q. Based on Lumen per watt Ratio what is more efficient to operate, MH or HPS?
A. HPS gives a higher lumen per watt ratio than metal halide and the bulbs often last up to twice as long. The 600 watt HPS has the highest lumen per watt ratio of any HID bulb. But for growing MH has a higher PAR value than HPS but often isn't enough in the red range of the spectrum, this is why a mix of both is required for optimal growth. Or the use of full spectrum bulbs is replacing mixing the MH with the HPS. The bulb manufacturers are doing this for you. "
"Well designed, compact system will give you years of fantastic light (remember, 600 Watt systems are the most efficient providing more lumens per watt of electricity). All cords are detachable so you can hang your light with ease. Superior light output will cover a 3' x 6' area or a 4' x 8' area. "
"I agree with potroast, 3 x 600w HPS's would be better than 4 x 400w HPs. The 600w HPS is the most efficient in terms of lumens per watt of any of the HPS systems. 3 x 600HPS's would output 3 x 90,000 lumens = 270,000 lumens, the 4 x 400w HPS's would output 4 x 55,000 lumens = 220,000 lumens. Plus the 600w systems would be only marginally more expensive to run, 3 x 5.7amps on a 120v system is 2052 watts, 4 x 400w would be 4 x 3.8 on a 120v system would be 1824 watts. So for 228 watts more you get another 50,000 lumens.
The air cooled reflectors, if set up properly would allow you to get your reflectors to within 12 inches of the plant tops without burning them, even lower depending on how efficient your ventilation system is. I think it would be a bit much to expect the vent system for the 3 air cooled hoods to also ventilate the area as well, so you'll have to set up a separate system for ventilating the area, probably with a charcoal filter.
Don't veg with the HPS's though, get some MH conversion bulbs or switchable ballasts that would allow you to switch over from HPS to MH for vegging. There are ballasts on the market than can run two lights from them, but they're not cheap. Aurora do an air cooled reflector and twin 600w ballast, but it's about 1000 USD."
