Signs of a Clog:

The first sign of a potential clog is the presence of excessive amounts of water in the NFT return troughs. If you notice that there is more than the typical ⅛ to ¼ inch of water in the bottom of an NFT return, this is a potential sign if a clog.  If the clog becomes a blockage, the return may fill to the point of overflowing.  Overflowing NFT returns, especially when their drains are not fully blocked, will typically leak only a little water, hiding the scope of the problem. As with any leak, if you see water on the floor, you should immediately try to determine the source of the leak. Overflowing NFT returns will normally leak from the area where rails are inserted into the return, but may leak from other areas of the return depending on the condition of individual equipment in question. Water leaking from NFT returns will often travel along the aluminum rails that make up the frame of the NFT system, so water will often first be seen at the base of the legs that support the entire NFT system.

Required Tools:

  • Hose and water source
  • Channel locks (preferably two)
  • Needlenose Pliers
  • Solid white 10×20 trays
  • Hand towels
  • Mop or Shop Vac

Optional Tools:

  • Drain snake
  • Testing and dosing equipment

How do I remediate a return trough clog?

  1. If a clog occurs and a return begins to overflow, the first step should be to cut all power to the NFT system where the overflow is happening. This is to prevent damage to lighting or other electronics, and to reduce the rate of flooding. 
  2. Next, solid 10×20 trays should be placed underneath the returns to catch as much water as possible. 
  3. Inspect the scope of the clog. Determine if there are roots growing all the way through the drain and into the reservoir.
  4. Carefully use fingers or needle nose pliers to attempt to pull the root mass out of the affected return drain.  In the case that you find roots growing through the return drain into the reservoir,  attempt to carefully remove them from both ends of the drain.
  5. If the roots break and remain stuck in the return, the next step would be to dismantle the drain pipe where it enters the reservoir. First attempt to unscrew the union connecting the drain to the reservoir using your hands. If it is too tight to dismantle by hand, channel locks should be used (carefully, as the system is delicate) for leverage. When this union is taken apart, and roots are visible, again try to carefully remove them. If there are no roots visible, or removing them does not clear the blockage, insert a hose into drain from the dismantled union, and briefly turn the hose on to full pressure to push the obstruction up and out.
  6. If repeated attempt to dislodge the clog this way fail, you may use a drain snake to remove the obstruction. If this fails, full disassembly of the NFT return may be necessary, an operation beyond the scope of this article.
  7. When the clog is cleared, reassemble the union, ensure that the floor and any electronics and outlets are dry, and turn the power back on.
  8. Observe all returns for a few minutes, to confirm that all drains are fully clear and no water is backing up into the system, and that water is flowing normally throughout the system.  Depending on the amount of water lost, the system may need to be tested and dosed for nutrients and PH.