Aquarium water quality TDS sensor

ESPHome
32

Sorry for my late response, I’m not visiting this forum so often…

Finally I had to get rid of TDS meter, because even if was powered by esp every half hour, pH meter readings were constantly distorted. I removed multiplexer and TDS meter and now pH readings looks much constant. There are still big differences between max and min readings, but after using median it looks good and credibly:

pH_sensor
pH_sensor1646×449 55.6 KB

pH_sensor_median
pH_sensor_median1649×463 19.2 KB

I’m using simplest pH probe and board/module from AliExpress:
pH_probe
pH_module

It’s connected like here:

but without lcd and using 3.3V diverter based on 2k2 and 3k3 ohm resistors to be more stable.

After setting this up, pH V readings on A0 need to be calibrated with voltmeter and ph buffers:

filters:
      - multiply: 3.1
      # Measured voltage / 3.1 -> Actual pH (buffer solution)
      - calibrate_linear:
          - 2.244 -> 9.18
          - 2.487 -> 6.86
          - 2.783 -> 4.00

I think your formula is incorrect. After substituting 25 for the temperature value it should look like:

((id(tds_raw_v).state) / (1 + (0.02 * (25 - 25.0))))

but I’m not sure if you can simple use 25…