Both the WL500 and WL300 can be used to implement this application
In case you have available connection to the public water system, the automatics can be installed as a level indicator, to know the level of water in your tank.
WL-500
Conections
diagram of a level indicator using WL-500
Install Wl500 as indicated in the box (see technical details at this site) and then connect cables as indicated in the diagram below
Quality and Reliability
This product has been developed and tested under heavy duty. It's been manufactured using the best durable materials. WL-500 supports up to 16 Amperes.