Electronic Arduino project - EC optocoupler advice needed

Job ID: 37221383

Budget: $10 – $30 USD

How can I correctly connect an optocoupler for measuring EC sensor and PH sensor to a scheme. First of all, an electronic test needs to be carried out to ensure that the measurements do not influence each other. The currently used electronics distort the results of PH as soon as EC is connected.

PH sensor: https://s.click.aliexpress.com/e/_DBj7C55
EC sensor: https://s.click.aliexpress.com/e/_DEdyi43

Example solution: DFR0504 with STM8S103F3P6 - https://www.digikey.ch/short/8c079rr9