# Q&A: How to set up the calibration of the ITDS-01 water quality tester

**URL:** <https://community.inkbird.com/t/q-a-how-to-set-up-the-calibration-of-the-itds-01-water-quality-tester/1117>\
**Category:** Questions & Answers\
**Tags:** smart-sensors\
**Created:** [November 30, 2022, 3:54am UTC](https://community.inkbird.com/t/q-a-how-to-set-up-the-calibration-of-the-itds-01-water-quality-tester/1117 "2022-11-30T03:54:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Tania](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.inkbird.com/tania/32/88_2.png) [@Tania](https://community.inkbird.com/u/Tania)\
**Post date:** [November 30, 2022, 3:54am UTC](https://community.inkbird.com/t/q-a-how-to-set-up-the-calibration-of-the-itds-01-water-quality-tester/1117/1 "2022-11-30T03:54:20Z")

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In the new version, the ITDS-01 water quality tester has a calibration function.  
Please press the Hold button for 3 seconds, the default value of 100 will flash.  
Short press the Shift button, the current coefficient can be adjusted (range 50-150), and the coefficient is a percentage.  
Short press the Hold key to exit and save the current setting.  
For example, the default coefficient is 1, which is 100%. If the tds reading is 199, then the reading is 199_100% = 199  
If the coefficient is +0.1, then the reading is 199_110% = 218.9 ≈ 219  
If the coefficient is -0.1, then the reading would be 199\*(1-0.1)=179.1≈179  
Please note that if the ITDS-01 water quality tester is restarted, its calibration value will need to be readjusted.