Connect the slv2 unit to the rest of your reefkeeper. Then on your display find your slv2 and select your salinity probe, then select calibrate. The first calibration is out of water, make sure the probe end is dry. So select enter and make the set point 0 press enter. when the "raw data" stabilizes, then press enter. The next calibration is in the solution. Make the set point to what your calibration fluid is and select enter so raw data is flashing. Put your probe in the calibration fluid and wait for the number to stabilize. Press enter and you should be done