Adequate supplies of water are essential In New Zealand very few water supplies are of such low quality that they cannot be used for NFT production. The cost of operating NFT systems is increased when water of low quality is used. Every NFT installation contains channels of gullies in which the plants grow in a shallow film of flowing nutrient solution. The nutrient solution flows out of the ends of the gullies into collecting pipes and from the pipes into a sump. Pumps are used to circulate the solution from the sump through flow mains and headers into the gullies.
Fresh water is added to the sump to replace water evaporated by the crops.
Additional nutrients are added as nutrient stock solutions to the sump to replace nutrients absorbed from the nutrient film by the crop. An Introduction to the NFT System.