Attached is a picture of my chlorinator and a close up of the control knob. When I turn the dial to increase the chlorine to the pool (counterclockwise) it starts leaking behind/around the knob at a pretty good amount. I have to set the dial almost completely closed to keep water from running out onto the floor which makes less chlorine enter the pool. There doesn't seem to be many moving parts to this so it can't be that complicated. I first thought there was an O-ring where the knob is located but don't see any. Anybody else have this problem and how did you fix it?