Nutrient Film Technique
Nutrient Film Technique is a commonly used hydroponic method, but is not as common in aquaponic systems. In NFT systems, nutrient rich water is pumped down small enclosed gutters, the water flowing down the gutter is only a very thin film. Plants sit in small plastic cups allowing their roots to access the water and absorb the nutrients.
NFT is only really suitable for certain types of plants, generally leafy green vegetables, larger plants will have root systems that are too big and invasive, or they become too heavy for the lightweight growing gutters.
NFT is more commonly used in commercial aquaponics systems but can be successfully used in a hobby system provided that the water is filtered before it is used in the NFT channels. Unfiltered water from the fish tanks will contain many particulates which will attach to the plant roots and will ultimately stop their ability to take up nutrients and oxygen.