tunze nano auto top off

[violet21chewy]

I have this nano auto top off on an 8 gallon tank. This morning is the 4th time I have seen an overfill of water. I checked the sensor to see if there was an obstruction and it is fine. I don't know why it keeps overfilling. It is changing my salinity from 1.025 to 1.022. Please help!

 

[rvitko]

The most probable assuming it is not a siphon due to the reservoir water level being higher than the end point of the hose is that the magnet holder is affecting the movement of the float. The float switch is magnetic, the black ring in the float is a magnet which flips a switch in the post, on the very thin glass of small tanks the magnet holder may not be fully cancelled so the float is restrained by the magnetic field. Try placing a shim of 1/8" thick acrylic or rubber pad between the outside magnet and the glass.

 

[violet21chewy]

thanks for the quick response. the reservoir is below the tank. will try putting something in between the magnet and the glass.