The 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 or into a Calciumreactor 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 pH Controller has a BNC connection for pH Electrodes. The use of an original Aqua Medic electrode #220.10 is recommended.