NFT system built out of 6 inch pvc piping (if you are SOG you can use the 4 inch pvc larger plants will clog 4 inch though) unless you want to pay a grow shop for an NFT set up the PVC works the best that I have seen and it is cheap to build. All you need is PVC, Rubbermaid storage tubs, black tubing, small pond pumps, and if noise is not a problem you do not need airstones. The water falling back into the reservoir from the PVC will aerate the water.
The basic idea is to build U shaped PVC sticks for each reservoir. Connect the 2 ends into the reservoir for water return and run black tubing from pond pump in the reservoir out to the opposite end of the U. The water will flow down both sides of the U and return to the reservoir.
Growing fairly large plants I was able to fit 18 in each U with reservoir and 4 reservoirs/U's in a 12x10 foot room. 72 plants made a perfect canopy when vegged to about 18-22 inches before flower. But, you get the idea.
You will want to have an aero cloner for using this method as you want the roots long enough to reach the water flowing through the PVC.
