The Bluelab pH Controller automatically monitors and controls pH within reservoirs up to 200 gallons (760 liters). The flashing high/low alarm with control lockouts includes dosing lockouts to protect from over-dosing, and auto-resume dosing on restart after power loss to ensure fine-tuned pH levels. The plant-safe green backlit LCD with adjustable brightness features a large, easy-to-read display, with easy-to-navigate menus. The water-resistant and wall-mountable controller also includes a 13-foot acid/alkali-resistant dosing tube. For best results use with undiluted Bluelab pH Up or Down.