주요 사실

• Nutrient solution is recirculated rather than discarded — lower water and fertiliser consumption
• Examples: DWC, RDWC, NFT, ebb-and-flow, Dutch bucket with return lines
• pH and EC must be monitored daily — concentrations change as plants absorb differentially
• Pathogens spread rapidly through recirculating systems if root rot takes hold
• Full reservoir change every 7–14 days prevents salt and pathogen accumulation
• Requires a return drain from growing channels back to the reservoir