Raspipool sends alert for frozen risk (water temp below 5 degrees or outside less than 0 °C for 24 hours)
When this, you can put valves closed and remove the probes and save them inside home with water in the factory cover.
My 6€ ph probe is 2 years old and is working like a charm. Orp are more delicated.
It is really much easier than you think (for me it was the first time I did it).
You only need the material (very cheap, less than 40€), a saw and glue (especially for PVC).
1. Connect the bypass with the collars from the filter outlet until before the pump. Build the bypass without glue, to see how it looks and adjust the perfect cutting measures.
2. The thick tube (50mm = D50, where the probes are) is horizontal and as low as possible, to ensure that it never runs out of water. And recomended less than 3 meters from where the raspberrypi is (for not cables too long).
3. Chop the pipes with a dremmel with a rounded fat sander head. Test first on an unused pipe (with the collar on). Finally, when you have practice and the holes are perfect, make them on the main pipes (what you need most guts).