Refill control for fresh water

Motivation

Salt-water aquariums evaporate significant amounts of pure water. The salt contained in the salt-water does not evaporate. If evaporation continues, salinity of the salt-water rises to a level higher than in natural sea-water. Furthermore, cleaning devices like protein skimmers require a nearly constant water-level in the aquarium. Also, a low water level may damage the heater if that device is not covered sufficiently with water.

Implementation

The refill control refills fresh water from a separate tank to the aquarium.

• The water level is monitored by means of a water level sensor.
• The refill control actuates a metering pump if low water level is indicated.
• The refill control considers potential failure of the water level sensor (stuck at low or spurious behavior).

Water level sensor in operation