The stainless-steel sensor is a device that measures the water level in the tank. It is important to place it correctly for accurate readings. The sensor should be placed at the bottom of the tank, and any extra cable should be coiled up inside the tank as well. This way, the sensor can detect the lowest water level possible. However, if the tank has a lot of sludge or sediment at the bottom, then the sensor should be lifted slightly above it. This will prevent the sensor from getting clogged or damaged by the sludge. The sensor should still be as close to the bottom as possible, but not touching the sludge.