The Crystal Water Monitor is a battery operated IoT product, which means that it's WiFi chipset is rather simple and must use a 2.4GHz band for connectivity. A WiFi Mesh Network is a whole-home network system designed to give you the best WiFi coverage by using a main router and multiple "nodes" that work together to provide seamless, high-spoeed and reliable network coverage and access to the internet. One of the big features of these Mesh Networks is that it optimizes channel frequencies on each node to minimize interference and ensure seamless, stable connectivity across multiple connected nodes. For most products, such as PC's or mobile phones, you wouldn't notice anything when the channel is switched, because the transition is smooth. However in an IoT product, the simple chipset requires a reconnection and you may see a disruption and multiple reconnection retries. For an IoT product that is AC powered, the disruption would be minimal. For a battery operated product, this means battery drain and in some cases, significant battery drain. The good news is that there is a solution that many Mesh Network products provide.
For TP-Link Networks, they allow you to make changes specifically to your 2.4GHz band without affecting your 5GHz band. They have provided instructions for doing this on their support pages located here: TP-Link Changing Channel and CHannel Width on a TP-Link Router
Orbit WiFi
If you are using an Orbi WiFi Mesh Network, you may need to enable the IoT network in the Orbi settings in order for the Crystal Water Monitor to connect.
Most all IoT products require a 2.4Ghz WiFi Access point to connect to and this is not always enabled by default. To enable your IoT access point on your Orbi, here is the official Netgear knowledgebase article: Enable IoT Network on Orbi Mesh Network
Many mesh wifi network companies do have specific settings/workarounds for IoT products to prevent the channel optimization issue that comes along with it. If your Mesh Network is not listed here, that doesn't mean there isn't a workable solution. That just means we need to work further with your hardware vendor to get a solution to you. For us to be able to do that, please send us the make/model and firmware version of your WiFi Router and Access points, we will reach out to the company to get the right solution for you.