A recirculating hydroponic system (also called a re-circ or closed-loop system) is one in which nutrient solution is continuously or periodically pumped from a central reservoir to the plants and then drained back into the same reservoir for reuse. This contrasts with drain-to-waste systems, where runoff is discarded. Recirculating systems are more resource-efficient but require more active management of pH, EC, and pathogen control as the same solution passes through the root zone repeatedly.
Key Facts
- Nutrient solution is recirculated rather than discarded β lower water and fertiliser consumption
- Examples: DWC, RDWC, NFT, ebb-and-flow, Dutch bucket with return lines
- pH and EC must be monitored daily β concentrations change as plants absorb differentially
- Pathogens spread rapidly through recirculating systems if root rot takes hold
- Full reservoir change every 7β14 days prevents salt and pathogen accumulation
- Requires a return drain from growing channels back to the reservoir