pH controller design

General
13

I worked in various dyehouses for over 40 years so pH control is almost second nature to me.

Automatic pH control is extremely complex and has to take into account a number of variables:

  1. Total system capacity.

  2. Native water hardness.

  3. Strength of acid/alkali donors for adjustments.

  4. Accurate dosing of donors and time to reach pH equilibrium.

  5. A meticulous electrode calibration scheme (For hydroponics a 1 point calibration daily at pH 4.01 should suffice)

  6. Electrode contamination, electrodes need to be kept clean, and some are not suitable for continuous immersion.

There are automatic systems available but as always at a price.

https://www.hg-hydroponics.co.uk/ph-ec-dosers--monitors-483-c.asp

I would love to see a node-red solution, small peristaltic pumps are quite cheap too.

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