February 15,2022

Black tank sensors reading 2/3 full? Here’s the solution.

If your RV’s black holding tank sensors aren’t working correctly and giving you inaccurate readings, you’re not alone. RV black tank sensors frequently give false readings due to the residual waste and toilet paper buildup on tank walls, causing the sensors to read 2/3 full even after dumping. The easiest way to clean your sensors is with a drop-in packet called Commando that restores sensor function in as little as 12 to 24 hours— with no agitation or scrubbing required.

RV owners often report their black holding tank sensors reading 2/3 full, even after emptying the tank. If you don’t know how full your holding tank is, you don’t know when to dump it. You’d likely empty your tank more frequently to be safe, leading to solid waste buildup, often referred to as the poo pyramid.

If you suspect your sensors aren’t reading correctly, you need to use Commando. 

  1. Empty your tank, rinse out any chemical residue, close your dump valve, drop one Commando packet into the toilet, and flush
  2. Then fill your holding above your highest sensor or completely full. 
  3. Leave it in for a minimum of 12 hours. Commando is formulated to work in as little as 12 to 24 hours for those in a hurry, but it will not hurt your tank to leave it in longer for more stubborn holding tank issues or clogs. 
  4. Empty your tank. Rinse again. You can now add your deodorizer, refill with 1.25 gallons of water for every 10 gallons of holding tank capacity and continue using the toilet.

Commando works its magic by releasing natural enzymes into the tank, which digest and liquefy waste and paper. Use as directed every three months to lubricate valves and seals and keep tank walls free from buildup. We also recommend adding it to your RV winterizing routine.

The next time you’re at your RV dealer, pick up a bag of Commando.