As much as it is a pain, calibrating your probes on your various aquarium controlling equipment is essential. The readings on pH and conductivity probes can drift wildly as the they age, and they can trend up or down if they aren’t calibrated regularly and replaced when necessary. Obviously, if the probes aren’t reading the proper number, then your calcium reactor, for example, may not provide enough calcium to your reef or it may provide too much and waste CO2. Fortunately, calibrating is simple. Place the probe into the correct standards or buffers, swirl them around for a bit, and put a button or two on your controller. It’s that simple, and most probe calibration solutions are really inexpensive.