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How it works

Water, just like metals, conducts electricity.  Everyone knows you should never stand in water when there is a thunderstorm because you might get hit.

If you are showing a full reading on your gray and black holding tanks, it is because electricity is flowing between the probes.  A circuit was established between the monitor and your tank probes, through the water or sludge.  This is why a red light appears on your monitor, showing you that you may be 1/3 full, 2/3 full or completely full.

But what if you are showing a full reading, when you know that your tank is empty?

The problem exists because sludge builds up on the probes and alongside the tank.  This slimy sludge is able to conduct electricity.  With current probes, the buildup on the probes of the tank creates that complete circuit.  Thus, causing your light to go on.

Here's a short video that will demonstrate for you why your current black and gray tanks show that they are full, when you know that they are empty.  It will also demonstrate why the Horst Miracle Probes work.

This Product is

The patent pending Horst Miracle Probes will solve your tank reading problems.


  • The probe itself is a self-cleaning probe.    The stem part is covered with Teflon tubing so sludge simply cannot stick to it.


  • The Teflon tubing is not conductive.  Thus, no communication ( or circuit ) can be made between the tip of your probe, and the slimy sludge buildup that is on the inside wall of your tank.


  • A complete circuit can only be made when actual water and sludge levels make contact with the tips of the probes.


  • Toilet paper and other matter that may get caught on the probe is not an issue, as the black water probes have a 'roof' over the copper tip.


In the past, recommendations have been made to drive around with ice cubes in the tank or using chemicals to temporarily solve this problem.  None of this is necessary anymore. 

Just change the existing probes with Horst Miracle Probes and eliminate embarrassing surprises.



Black Probe:
Probe for Black Water Tank in RV


Grey Probe:


Watch this demonstration video done by Jim Grich of the American RVer.




Here's an example using a transparent tank.  
The 3 probes on the left are placed so that they sense the different water levels.  Electrical current flows between the metal tips of probes connected to a PLUS (+) of a battery and the one on the right, which is connected to the MINUS (-) through the liquid.  This current lights up the LEDs.

 Example Tank using Horst Miracle Probes




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