Hope this is the correct forum for this. I have an issue with the pH in my Ca reactor. Noticed the pH was up over 7 a month back. Despite turning the dial down on my Milwaukee pH controller it would not budge by much. Controller pH was dialed down to 6.6 and pH did not move. So thought the pH probe was bad and changed it out. Calibrated the probe and it seemed fine for 3 weeks with reactor pH at 6.7 which is typically where I keep it. Noticed my alk dropping so checked the pH controller and pH is again 7.1. Cannot figure out why it is doing this. Is it that I have a bad probe? Or is there something else. Media and CO2 tank are full and CO2 is bubbling correctly. I have been using a Ca reactor for 5 years and never ran into this issue. Any help will be appreciated.