Hach pH Manuel D'utilisation page 19

Note: A video that shows how to replace the salt bridge is available on www.Hach.com. Go to the salt bridge
webpage and click the Video tab.
Items to collect:
• Adjustable crescent wrench
• Large tweezers
• Salt bridge
• Standard cell solution
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• Gel powder , ⅛ teaspoon
1. Clean the sensor. Refer to
2. Replace the salt bridge and the standard cell solution. Refer to the illustrated steps that follow.
If the reservoir for the standard cell solution contains a gel (not usual), use a jet of water from a
water pik-type device to remove the old gel at illustrated step 2.
(Optional) If the process water is near the boiling temperature, add gel powder to the new
standard cell solution at illustrated step 4 as follows:
a. Pour 1 level bottle cap (⅛ teaspoon) of gel powder into the reservoir for the standard cell
solution.
b. Pour a small amount of fresh standard cell solution into the reservoir.
c. Mix with the powder until the solution becomes thick.
d. Add small amounts of solution and mix until the gel level is at the bottom of the salt bridge
threads.
e. Check for proper gel level by installing and removing the new salt bridge. A salt bridge
impression should remain on the gel surface.
3. Calibrate the sensor.
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(Optional) Add gel powder to the standard cell solution if the process water is near the boiling
temperature. The gel powder decreases the evaporation rate of the standard cell solution.
Clean the sensor on page 18.
English 19