Foxx project water sensors stop working?

Hi All, looking for some advice on using Foxx project water sensors. I’m using them to monitor an aquaponic system so every 15 mins they will see water and confirm that my system is working correctly. They work great to start with but then just stop working. They seem to just stick on whatever condition they were seeing at the time. If I remove them and setup again they will work for a day or so but then stop again. Does anyone know of a solution or have experience with this issue? All of my other sensors are working fine. Both of my water sensors have the same issue.