The JBL ProFlora CO2 Valve solenoid valve reliably controls the supply of CO2 to the aquarium. The CO2 supply can be interrupted at night by the time switch on the lighting or, in combination with electronically ph controller, the CO2 supply can be varied according to the pH level. The JBL Proflora CO2 Valve has been designed to operate with JBL pressure reducers, but it is also suitable for use with almost any other commercially available pressure reducer.Why do you need a solenoid valve or a night shut-off?Since plants only need CO2 for photosynthesis during the lighting phase, you can turn off the CO2 supply at night. To save you having to turn the CO2 bottle on and off, there are solenoid valves which can be controlled by a timer. The timer then switches, say, the light and the CO2 supply on via the solenoid valve in the morning and off again in the evening. Shrewd aquarium owners will immediately recognise that the solenoid valve quickly recoups its cost price by saving the CO2 by