Bluelab pH Controller is a hands-free monitoring and dosing of solution pH levels. Our clever pH controller automatically monitors and fine-tunes the pH levels for you. You simply set it and forget. The pH is taken care of. For use with reservoirs up to 200 US gal/760 L. Plant-safe green backlit LCD with adjustable brightness and large, easy-to-read display. Easy to navigate menu to program, adjust settings and calibrate by a simple push of a button. Flashing high/low alarm with control lockouts to protect from over-dosing. Auto resume dosing on restart after power loss. Includes: water-resistant, wall mount housing, 13 ft acid/alkali resistant dosing tube, international power supply, replaceable double junction pH probe and temperature probe (for pH ATC). Use with undiluted Bluelab pH Up or Down. 6 month guarantee for Bluelab pH Probe.