[martym]

Tang Daddy- That is basically how it is running. I do have 2 monitors. But for me the controller is in the main tank. The monitor is in the effluent just before it drips into the tank. So when the tank is above 8.01 the Rx turns on. The effluent then drops down to 6.7 and remains there until the ph in the tank drops below 8.0.
Yesterday for an example, I managed to leave the window in the room where the aquarium is open all day. The Rx came on at around 10am and was still running when I went to bed at 9:30pm. The Ph in the MD is at 7.9 this am (5:30am) So it is running, and maintaining the values that I'm after, for the most part. My Alk does dip down to 7DkH just before my bi-weekly WC. My concern is the Ph in the main display had dropped to below 7.8, which is a bad thing. I was hoping that I could keep it up a bit higher than that.