Easily and inexpensively extend the life of Hach differential sensors by periodically replacing the salt bridge and standard cell solution. This process only takes about 5 minutes. Although Hach differential sensors may initially cost more than standard combination sensors, they pay for themselves many times over if you periodically regenerate the probe with the inexpensive salt bridge and standard cell solution. For optimum performance, Hach recommends that differential sensor salt bridges and standard cell solution be replaced every 6 months.

The following illustration shows replacement of salt bridge and standard cell solution for a Hach LCP (Liquid Crystal Polymer) body material pH sensor. Follow the same instructions to replace the salt bridge and standard cell solution for other pH / ORP sensors, but use an adjustable wrench to unscrew the salt bridge from the sensor.

Remove the salt bridge by holding the sensor in an upright position and turn the salt bridge counterclockwise using a socket wrench or nut driver. Take care not to damage the glass measuring electrode.

Pour out the aged standard cell solution. Thoroughly flush the standard electrode chamber with fresh standard cell solution.

Fill the standard electrode chamber to the top of the thread with fresh standard cell solution.

Install the new salt bridge, making sure the 0-ring is intact. Turn the salt bridge clockwise until finger tight. Then tighten with a socket wrench or nut driver approximately 1/4 turn, Do not over tighten.

Calibrate the system and return the sensor to the process. If you have additional questions or if you need to order replacement salt bridges or standard cell solution, contact us at 877-215-9090.