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Recirculating vs. Drain-to-Waste Hydroponic Systems

Posted by Zack Foust, Sales Representative on 6/26/2019

CropKing hydroponic systems can be placed into two broad categories: drain-to-waste and recirculating. A drain-to-waste system delivers a nutrient solution to the crops and the “run-off" is expelled. Sometimes these systems are also referred to as “feed to waste” systems. In comparison, a recirculating system delivers a nutrient solution to the crops and the “run-off” is returned back to the reservoir to be fed to the crops again. Many growers want to use recirculating systems in order to conserve as much water as possible, but growing certain crops using recirculating systems may become more expensive, require special care, and in some cases, growers may end up using more water than growing the same crops using drain-to-waste systems. The pros and cons of each are outlined below:

 

Drain-to-Waste

Re-circulating

Pros

  • Crops fed fresh nutrient solution with same EC and pH each irrigation cycle
  • Many different kinds of growing media could be used
  • Lower probability of clogged emitters
  • Water-borne disease transmission less likely
  • Certain pest control products may be applied effectively as drenches (read labels for more information)
  • Flushing of salt accumulation is straight-forward
  • Nutrient solution and/or water is recycled
  • Fewer nutrients may be used throughout production
  • Fertilizer leaching from nutrient solution is minimized
  • Reduced water use
  • A variety of hydroponic systems can be recirculating

Cons

  • Increased water use
  • Increased fertilizer use may add production costs
  • Fertilizer and pesticide leaching may occur more often
  • Salt accumulation may occur several times throughout production
  • Limited to certain hydroponic systems
  • EC and pH of nutrient solution may fluctuate
  • Ratios of individual nutrients in solution may fluctuate
  • Probability of water-borne disease transmission may be high
  • Flushing of salt accumulation may be labor intensive
  • Without appropriate action, algae and or biofilms may clog emitters

 

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