DWC keeps roots submerged, so oxygen is added using an aerator. NFT uses flowing water that naturally brings oxygen. Therefore, DWC needs extra oxygen supply, while NFT’s moving water provides enough for roots.
Class 8 Vocational Education Textbook Work with Life Forms Chapter 1 Hydroponics Growing Plants without Soil question answer
Class 8 Vocational Education Kaushal Bodh Project 1 Hydroponics: Growing Plants without Soil solutions
In the Deep Water Culture (DWC) system, roots are fully immersed in water, which can run out of oxygen. So, an air pump or aerator is needed to provide oxygen for root health. In the Nutrient Film Technique (NFT), a thin stream of water flows continuously over the roots, naturally carrying dissolved oxygen. Thus, NFT doesn’t need an aerator because its water movement keeps roots aerated and healthy.