Maximum Yield Australia/New Zealand July/August 2020 | Page 37

Systems Differences and EC The main EC differences between an open substrate-based system and a closed system such as NFT are that generally drain-to-waste systems are run at a lower EC than if the same solution was running in a recirculating solution culture system. This is because the solution applied to a substrate-based open system is different to the actual EC in the root zone (and hence drainage solution). With open systems, the EC and pH should be measured in a sample of the drainage solution flowing from the substrate after each irrigation as this is what these will be directly surrounding the root system. The EC and pH of the drainage solution can then be used to make regular adjustment to the irrigation solution to maintain the correct levels directly around the root zone. Apart from differences in EC, nutrient formulations don’t differ much between most open and closed systems unless the substrate in an open system has an effect on the balance of elements in the root zone. Open and closed hydroponic systems both have their own pros and cons and suitability to different growing situations and inputs. Understanding how each system influences the composition of the nutrient solution over time and the correct monitoring and management technique for each is essential in optimising plant nutrition from whichever system is being used. the PINNACLE of gas detection has ARRIVED MEET THE CM-7000 CO2 MULTI SENSOR SYSTEM • Up to 12 remote sensors • Cutting-edge, 0-5% NDIR CO2 Sensor • 4 Standard Alarm Levels, 3 Separate Relays • Customizable audible & visual alarm settings • Key driven shut-off capability (Reset Unit – CM-7002) • Used in agriculture facilities, worldwide [email protected] | 877-678-4259 tweet it. follow us on twitter. @max_yield maximumyield.com Maximum Yield 37