The nutrient film technique (NFT) was designed to reduce the sheer amount of water required for bed and trench style hydroponics. It does a great job of doing just that, but it also becomes less effective at working within an aquaponics system for the same reason.

Because aquaponics attempts to utilize freshly created nutrients from fish waste rather than highly controlled nutrients dispensed from a bottle or bag, there’s a lot more fluctuation on a daily basis in the water quality and nutrient supply. With the NFT system, plants are grown in pipes or small trenches that are only flushed a small amount of water rather than kept full constantly (like DWC or media filled beds). The roots get plenty of oxygen because they’re not floating in water, but they’re also much more sensitive water quality as well as any delay in water release.

For most beginners, an NFT system requires too much expertise and constant maintenance when compared to DWC or media bed systems; especially for commercial use.

Benefits of NFT:

• No need to buy growing media, although most NFT systems still use some kind of net or plastic pot to support the plant roots.
• No controllers needed for timed release of water, as is used in the ebb and flow system.
• Faster application of specific nutrients to remedy a deficiency, but more work maintaining a steady nutrient supply and water quality.
• Low nutrient requirements for strong plant growth, as the roots absorb most or all of what’s supplied, which necessitates low stock rates of fish in an aquaponics system.
• Constant flow washes waste to the end of the pipes or trenches for relatively easy clean-up.