It's been an interesting week for the reef. Alkalinity Testing alkalinity, I noticed that it was getting a little low, probably around 7 dKH rather than the normal 8 dKH. To raise it up slightly, I adjusted the pH controller from the 6.5 setting to 6.2 instead. The next day, I checked on the calcium reactor to find that nothing was coming out. Annoyed, I opened up the needle valve a quarter twist and flow resumed. The following day I checked on it again, and again no effluent. ...