uh- how big are these plants? They'd have to be 6+ foot trees to use 5L/day- and if they were that size, no commonly available artificial light would ever penetrate more than halfway through the canopy.
Care to revise that estimate?
We are currently running a DWC system using 27 gallon tough box totes. Each tote holds one plant. The room is 5 x 12 feet with four 1000 w lamps. There is one tough box under each lamp. The system is connected together with 3/4 inch poly hose and connected to a reservoir. The reservoir has an auto-top off system, and the system circulates continually.
During flowering the system uses between 15 - 20 gallons per day. That is 4 - 5 gallons per day per plant.
We average 1 - 1.5 lbs per plant. When the plants are ripe, some of the tough boxes are so completely filled with roots that it is one big block of roots. Because the boxes are so wide, the plants grow horizontally faster than they grow vertically. Because of the horizontal growth, the four plants fill the whole room wall to wall, but the height is only about 4 - 4 1/2 feet when they are done. I top them one day before I initiate flowering. The wider root system gives wider buds. The nugs are the size of golf balls and bigger when dry.
My experience with DWC is the smaller the container, the taller the plant. The bigger/wider the container, the wider the plant, and the wider the buds. Of course, in the end the yield is proportional to the amount of light the plant recieves. I like only having to mess with four plants instead of the 15 I had before. I also like the golf ball/tennis ball sized nugs, very easy to trim.
The main problem I have with this system is cooling and aeration. Because the boxes are so wide I use two 8 inch flat disc airstones per box. I use 3/8 inch tubing between the pump and the stones rather than the 1/4 inch that comes with the pump. I use a 110 liter per minute airpump between the four boxes.
http://www.hydroponics.net/i/133881
This delivers so much aeration that my solution level rises about 3 inches from all the air in the water. Hyper aeration. Even though my system is running temps in the mid 70s, I have had no root rot with this much aeration. I also use a shot of H2o2 every day to keep things sterile. Before I used two of the little cylinder shaped airstones, but the roots only filled about 1/3 of the tub and I had occasional root rot problems. I am now in the process of figuring out how to chill the system. I may just insulate the boxes and the reservoir and use some sort of simple chilling system.
They vegetate for about 30 days in this system.
