Incorrect Grey and Black Tank Lights

[SBeazley]

I just drained my Grey and Black Tanks but both are reading full when I press the Lights inside? Is this a common problem? Is there a fix? Skot

[Grumpy]

Originally Posted by SBeazley

I just drained my Grey and Black Tanks but both are reading full when I press the Lights inside? Is this a common problem? Is there a fix? Skot

Welcome to the wonderful world of "Tank gauges".

Any TP, food particles, grease, etc that is stuck on the sensor will give you a false reading. Sometimes when the tank dries you will get a good reading.

The only very accurate gauges are after market made by "See Level", but could be a challenge to install with a sealed underbelly.

[TWP723]

Most likely something is hung on the sensor giving a bad reading. Shine a flashlight down into the toilet to see if has drained completely. You can fill both tanks up with water then drain again. It may get whatever it is on the sensors off.

[madmaxmutt]

Originally Posted by SBeazley

I just drained my Grey and Black Tanks but both are reading full when I press the Lights inside? Is this a common problem? Is there a fix? Skot

It is more than common, it is nearly guaranteed to occur from time to time. Add a half cup of Calgon water softener, and fill the tank just to full. Drive it around for a few minutes, and drain the tank. We use Calgon, bleach, and a cup of laundry detergent, with every use. Rarely have issues.

If you have a black tank flush, use that.

[Tunce the traveler]

The day before I start my trip I fill both tanks about 1/4 full & 1/4 cup of Dawn ( more than that I consider overkill). When I reach my destination ( about 350 miles) I drain both tanks & do a rinse then I’m good. Same on my return trip home ( 10 weeks later). I dump on the interstate rest stop but not every stop has this convenience along the way. Look on the rest stop sign and it will show a trailer with a dump tank so you know enough to pull into that one. Don’t forget to do a rinse while your there and its a good time for the wife and kids to stretch their legs for 15 minutes.
I have the wand that spins the spray so when the black tank valve is open I put it down the toilet and let it do it’s job.

[norty1]

I do not depend on my indicator lights. As you get used to the rig you will know when it's time to dump the tanks. We can go to the bank on timing because we adjust how much goes in based on the availability of dump stations. Navy showers, distributing dish water to the outside, Thetford valve on the tank dump to equalize grey tanks, using facilities if available...etc.

Many say they never have problems with them but I have spent enough grey matter trying to make them accurate. The only permanent solution is SeeLevel sensors.

[RogerR]

I bought some very cheap "orange clean" antibacterial soap at Dollar Tree. Added a cup or so to my grey and black tanks. After a few days travel and a couple of dumps my lights were back in action! Also, kept all black tank odors down.

Now at home and added a teaspoon of septic tank treatment to each tank and filled them. With temps in the 90s hope the bacteria will "digest" anything left in both tanks.