YOU DO NEED A GOOD SET OF ROOTS BEFORE THEY GO IN AND THE PIPES NEED TO BE SEALED TIGHT TO BUILD UP CONDENSATION (taking caps of)and slightly deeper water .
The nutrient film technique (NFT) was developed during the late 1960's by Dr Allan Cooper at the Glasshouse Crops Research Institute in the U.K. With the NFT system, a thin film of nutrient solution flows through plastic channels, which contain the plant roots with no solid planting media. The root mat develops partly in the shallow stream of recirculating solution and partly above it. It is extremely important to maintain this basic principle of a nutrient film because it ensures the root system has access to adequate oxygen levels.The key requirements in achieving a nutrient film situation are described by Cooper (1996) as being:
1) To ensure that the gradient down which the water flows is uniform and not subject to localized depressions, not even a depression of a few millimeters.
2)The inlet flow rate must not be so rapid that a considerable depth of water flows down the gradient
3) The width of the channels in which the roots are confined must be adequate to avoid any damming up of the nutrient by the root mat. If inadequate, it is to be expected that yields will be directly proportional to channel width.
4)
The base of the channel must be flat and not curved, because there will be a considerable depth of liquid along the center of a channel with a curved base, merely because of the shape of the base (Cooper 1996).