The Aqua Medic pH Control-Set is a high-quality pH measuring and control system for freshwater and saltwater aquariums. Includes: Aqua Medic pH Controller, pH-sensor, sensor holder, pH-test fluids (4,7,9) and Aqua Medic M-ventil solenoid valve.The Aqua Medic pH Controller is a precision instrument for controlling the pH value in aquaria. In combination with a CO2 system and a solenoid valve the pH can be maintained at a constant level, and the CO2 supply to aquatic plants can be controlled. The unit is supplied with a large LED display and the control range is digitally adjustable from pH 3.5 to 10.5. The direction of adjustment can be set up or down. The Aqua Medic pH Controller has a BNC connection for pH electrodes.In addition to the Aqua Medic pH Controller, the Aqua Medic pH Control Set also contains a high-quality Aqua Medic pH electrode, the pH 4/7/9 test solutions required for calibration, an electrode holder for 4 electrodes and the solenoid valve for controlling the CO2 syste