Pardon if this has been asked and answered... I have a Reefkeeper Elite with 3 PC4's and a SL1 unit. I only had the temperature input until recently when I decided to purchase a BRS pH probe. When I plugged it into the SL1, there is no indication that it was recognized. When I highlight the SL1 on my input and hit enter, no function screen comes up either. I am getting temperature readings and the SL1 flashes when I select input. Is the unit bad or am I missing a step?