The pH controller 2001 C 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 pH controller has a BNC connection for pH electrodes. The use of an original Aqua Medic plastic shafted electrode is recommended.