Hello @NilkOne!!
Great project in progress!! For the following two points:
I use the Sonoff TH16 and it does the job very well with Tasmota flashed on it.
For pH measurement, unfortunately I haven’t found anything low-cost yet. At domadoo, there is the REDOX MEASUREMENT PROBE FOR X200PH EXTENSION MODULE to be coupled with X200PH EXTENSION MODULE and with IPX800 V4 …
This comes to approximately €250… Well, it is capable of doing other things at this price but it’s expensive.
If it interests you, I think @cce66 has made a tutorial to link the IPX800V5 with Gladys via NodeRed.
Good luck with your project and I will be interested in following your progress!!
Edit: I found the tutorial again