# Grey Tank Showing 2/3 Full



## CaptFX4 (Jan 20, 2012)

My grey tank is showing 2/3 full and I know it is empty. I filled it with fresh water and dumped it and left the valve open for an hour.

Just tryig to figure out what the issue could be.

Thanks for any advice.

Capt


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## KTMRacer (Jun 28, 2010)

CaptFX4 said:


> My grey tank is showing 2/3 full and I know it is empty. I filled it with fresh water and dumped it and left the valve open for an hour.
> 
> Just tryig to figure out what the issue could be.
> 
> ...


welcome to the world of the sensor issues. The tank sensors are just the head of a bolt protruding through the tank wall insulated by a very thin rubber washer. (commonly called a "well nut") the light up when there is low to medium resistance between any probe and the "ground" probe. So..... any kind of crud buildup can end up giving you trouble. black tank is worst, grey next. This is by far the most common reason for bad readings.

couple of suggestions:

1) next time your out, add some water softener (calgon) to the grey tanks along with a scoop of laundry detergent. That may clean the sensors.

2) for a longer term solution pop out the existing sensors (yes it means opening up the underbelly) and install Horst Miracle probes. They work on the same principle, but instead of a bolt head and rubber washer, the grey tank sensors have a long teflon insulator and a very small wire probe. Much less likely to give an erroneous reading. For the black tank it it similar but there is also a "hood" over the wire so TP etc. doesn't get stuck on the probe and cause it to give a false reading. The horst probes have worked very well for us, along with putting some laundry detergent and calgon in the black and grey tanks to help keep the sides clean.

The total solution is a external capacitive sensing probe, but they are pretty spendy.


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## CaptFX4 (Jan 20, 2012)

KTMRacer said:


> My grey tank is showing 2/3 full and I know it is empty. I filled it with fresh water and dumped it and left the valve open for an hour.
> 
> Just tryig to figure out what the issue could be.
> 
> ...


welcome to the world of the sensor issues. The tank sensors are just the head of a bolt protruding through the tank wall insulated by a very thin rubber washer. (commonly called a "well nut") the light up when there is low to medium resistance between any probe and the "ground" probe. So..... any kind of crud buildup can end up giving you trouble. black tank is worst, grey next. This is by far the most common reason for bad readings.

couple of suggestions:

1) next time your out, add some water softener (calgon) to the grey tanks along with a scoop of laundry detergent. That may clean the sensors.

2) for a longer term solution pop out the existing sensors (yes it means opening up the underbelly) and install Horst Miracle probes. They work on the same principle, but instead of a bolt head and rubber washer, the grey tank sensors have a long teflon insulator and a very small wire probe. Much less likely to give an erroneous reading. For the black tank it it similar but there is also a "hood" over the wire so TP etc. doesn't get stuck on the probe and cause it to give a false reading. The horst probes have worked very well for us, along with putting some laundry detergent and calgon in the black and grey tanks to help keep the sides clean.

The total solution is a external capacitive sensing probe, but they are pretty spendy.
[/quote]

Thank you for the reply. We recently got back from Myrtle Beach and I'm wondering if there is sand or something in there from giving my 3 boys (6, 3, and 1 yr) baths in there.

I have one more trip planned so I'll add the items you mentioned above before I leave and fill it 1/2 way and hope it acts as a washing machine and aggitates the tanks on the way.

Thanks again.

Capt


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