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Cleaning tank sensors

by RV Forum member Carson

Try this inexpensive way to restore black tank sensor accuracy and generally clean the interior of the tank. Proportions for Class A Motorhomes, adjust for smaller tanks. It restored my severely challenged system on the first try. This is est done a day or two before departure on RV trip.

Start with an empty tank.

Fill tank half full with clean water.

Make a mixture (pail full) of hot water with:

  • 2 cups BORAX*
  • 1 cup laundry detergent, powder
  • 1 cup household bleach
  • 1 cup Salt
  • 1/2 cup TSP or TSP Substitute
  • 1/2 cup DAWN Dishwash detergent (DAWN only)

Dissolve well and pour mixture into black water tank.

Drive Rv to slosh mixture around in tank and let sit until RV trip starts.

Just prior to departure, add 4 bags of ice cubes.

At arrival at campsite, after several hours of driving, dump content.

Refill tank with clean water, once or twice, and flush (dump) each time.

Sensor operation should now be restored to new condition.

Never leave tank empty during storage; Fill at least 1/4 full with clean water and a dose of RV deodorant, to prevent dry-out.

Note: This mixture is relatively eco-friendly and non-fuming.

Note: The same may done with Grey Water Tank, except Ice cubes.

* Borax is a water softener - ph 8.0, and cleaner.

This mixture is designed to break down any cellulose material and other material attached to or in the vicinity of the electrodes/sensors.

If water is kept in the tank at all times, moisture will prevent hardening of this material on the walls of the tank,(especially during long term storage), a major cause of sensor sensitivity failure.