How do I site the Smartlevel to get the best results?

There are 2 Aquarium set ups commonly used :
1. Aquarium and Refill Tank: in this situation the sensor is placed in the aquarium with the sensor max mark being set to the water level you want. Use the magnet to secure the sensor in this position. Then the pump must be placed in your refill tank with water feed from the pump returning to the aquarium ( this tops up the Aquarium should aquarium level fall to minimum).
2. Aquarium Refill tank and Sump: in this situation the sensor is placed in the sump with the sensor Max mark being set to the water level you want. Use the magnet to secure the sensor in this position. Then the pump must be placed in your refill tank with water feed from the pump returning to the sump ( this tops up the sump should the Sump  level fall to minimum)