Black Water Tank

[Ohsirr]

I'm having a problem with my levels for my black water tank. I've emptied the tank several time and it's still reading 2/3 full.
I've filled the tank with water and water softener dumped it and repeated this action several times. Right after dumping the tank it shows empty but then when I drive home and park it, level it shows 2/3 full again.

Any help at this time would be great.

[Gary RVRoamer]

Pretty common problem with the waste tanks. Crud gets on the sensors and they give false readings. You can clean the tank by adding an enzyme-type septic tank treatment like Roebic 57 or 67 and letting it sit for a couple days, but the problem will recur. The only permanent solution is to switch to external sensors such as the Garnet See-Level.
SeeLeveL RV Gauges by Garnet Technologies Inc.

[Ohsirr]

thanks for the info. But if I replace the sensors do I need to replace the tank?

[OldChief7155]

There's a system made that reads thru the tank wall. Winnebago uses it. I believe they can be installed after market. That's what I would go with to eliminate the problem.

Somebody will give the name out before too long. It just escapes me right now.

[Batman_777]

New RV tank sensors are often using a new technology that is in a stick-on pad. The sensor sticks to RV tanks with double-sided stick tape.

Below is a pointer to something that is the same or similar.

http://www.touchsensor.com/pdfs/1928...r_System_3.pdf

http://www.sealandsanitation.com/Sen...0RV%20page.pdf

There are no moving parts and nothing is drilled.

There is a problem: They are subject to RF inteference or any other Electro Magnetic Field (Noise to the sensor)

I have been thinkiing of a way to reduce any noise interference with some kind of insulator. Maybe someone else has and idea. I used some aluminum duct tape over the sensor pad hoping it would displace signals, but instead, it might be an antenna. Hmmm,,,,

I moved the sensor pad around the tank and found a place towards the top left side (since this sensor if for full detection) that works best, but it still gets false readings.

[Clay L]

The Winnebago non-contact system is called TruLevel and has been standard since 2005.
Mine was installed at the factory on 2005 as an aftermarket item.

The bad news is - it isn't a perfect solution either.
Although most people talk about the sensors being the problem it is actually gunked up tank walls that fake out the sensors.

Right now the tank walls are coated enough to make the black water read full all the time. I have pressure washed the tank through the toilet twice and it works for a while afterwards and then starts reading wrong again.
The gray water "full" LED works okay but the 2/3 and 1/3 LED are always on.

If you can install a flush system on the black tank that seems to help to keep the reading accurate.

The SeaLevel system by Garnet seems to be one of the best systems out there but it can be fooled also. According to the manual on their site if the tank wall gets cruddy enough the system will stop reading which they say is your signal to clean the tank.

[Batman_777]

Maybe the surest way is to stick your finger in a plug hole to check for a full tank

Or use a dipstick

[scoutmstr]

I had the same problem with my tanks. After 5 years the black would show full most of the time. A simple check was to turn off water pump and look down toilet but that was a PITA.

I filled the tanks with water and blue Dawn mixture let it sit a day drained, refilled with clean water drained. Sensors now read correct. Every three or four years is on my schedule. I could get to the black tank sensors if needed but access to gray tank involves removing black tank. Not one of Rexhall's better ideas especially since I have a leak somewhere in the gray tank.

[DAN L]

Quote:

Originally Posted by Ohsirr I'm having a problem with my levels for my black water tank. I've emptied the tank several time and it's still reading 2/3 full. I've filled the tank with water and water softener dumped it and repeated this action several times. Right after dumping the tank it shows empty but then when I drive home and park it, level it shows 2/3 full again. Any help at this time would be great.

try a lot of ice cubes in the half full black tank. then drive the moho. i have to do this a couple of times a year.
i use a capful of calgon liquid water softener from wally world every time i dump also.

[azloafer]

Quote:

Originally Posted by DAN L try a lot of ice cubes in the half full black tank. then drive the moho. i have to do this a couple of times a year. i use a capful of calgon liquid water softener from wally world every time i dump also.

I wish that I could find Calgon around here. I have checked at Walmart and Safeway with negative results. The employee at Walmart said that several people have asked for it, but they just don't have it at their store. I ordered a couple bottles online, but it is expensive paying for shipping. I have yet to try Fry's in a neighboring town. I'll do that next week. Joe

[paz]

Quote:

Originally Posted by Ohsirr thanks for the info. But if I replace the sensors do I need to replace the tank?

Erroneous readings, especially for your waste tanks, is a common problem. That's the reason there are so many aftermarket sensors. A few manufacturers are using these new, through-the-wall sensors; but they are more expensive, so most use the old-style sensors even though they are useless.

After the problems we had with the tank sensors on our old travel trailer, upgrading our tank sensors was one of the first things I did when we bought our motorhome back in 2005. It was the best $300 we have spent on the motorhome.

You DO NOT need to replace the tank. For the SeeLevel sensors, you DO NOT need to drill new holes in your tank. The new SeeLevel sensors stick onto the exterior wall of the tank. The existing sensors can just be left in place. You use existing wiring to transmit the signals from the new sensors to a new panel inside the motor home. The panel for the system we chose fit in the same space as our old panel. I think I just needed to enlarge the hole slightly.

Another advantage to many of the aftermarket sensors is you can read the level of tank contents in as low as 1, 3 or 5% increments instead of 1/3, 2/3, and full. This is very helpful if you are camping without a sewer hookup.

Check the SeeLevel web site. They are currently having a sale with discounted prices. They also have a Customer Feedback page with links to do-it-yourself installs described right here on iRV2 (Joe-K and Warpath).

[speed racer]

When I clean both my tanks I put about 10 gal. of water and about a quart of PineSol in each tank. I drive to my next destination and empty and rense them. It not only cleans the tanks but every thing smells like a fresh green forest. I do this at least twice a year.

[AFChap]

A different replacement option is Horst Miracle Probes. They are replacement probes that use the existing wiring and display. The active part of the probe is away from the tank wall, and the black probes have a "hood" to prevent false readings from paper, etc. In most cases you can remove the original probes and use the same hole. On one of my tanks the walls are thicker so I had to drill new holes and countersink the outside head. That was not at all difficult to do. Mine took awhile before they started reading accurately, but they are good now. My coach has two panels off the same sensors, and apparently the outside panel board was causing the inside panel to act up. The Horst Probes are considerably cheaper than the other replacement systems.