An important note, after several years experimenting there may be some less expensive methods to re-use the sensors in your Beneteau or Lagoon based boats. Please see the bottom of this post for details. Black water tanks, poo-tanks, crude tanks or ick tanks. Keeping track of how full they are is not a fun task.On this and our last catamaran the tanks are wall mounted above the heads and only hold 81 liters (21 US gallons, 0.69 Barrels). This limited storage means we have to be aware of what we are holding in between pump-outs while at the dock or “sails to the pump-out” when you are anchored. This level tracking can cause some anxiety among members of the crew. *cough* Caroline *cough* Over the years we have developed several methods of checking tank levels without sensors. We have used our 2-million candle power flash-light, aiming it down through the…