The KH Guardian from Dr. Bridge is one of the most innovative controllers we have seen at Reef2Land. The KHG is an all-in-one device that automatically monitors and manages carbonate hardness values of a reef tank throughout the day. pH stability without constant manual dosing has been something that most reef hobbyists have desired for some time now. The Guardan Monitor takes nearly all the guess work our of trying to maintain your pH levels on your own. It continuously measures Alkalinity and is extremely precise with a testing accuracy of +/- 0.1dKH. Should you have any further questions regarding the KH Guardian please contact us.