Tank level sensors

[Motodad]

The grey and black level sensors in 13’ 31.5 RLTS seem to be a little hay-wire.
I will dump tanks and indicator panel will read anywhere from 1/4 to 3/4 even after a day or so. When I bought the trailer, they had a circuit board back ordered and it has been installed. I’m not so sure that’s the issue.
Anyone experienced this ?

[Jdmcla]

The sensors in my '18 Seismic are hit or miss every time. Have tried Calgon, dawn, warm clean water, hot clean water, cold clean water...still hit or miss. From some previous threads, it seems to be a common issue due to the kind of sensors in the tanks...evidently they're not float type sensors. Anywho, I'll follow along in case anyone has an answer.

[RoadrunnerII]

The sensors are basic probes in the tank. Basically they close a low voltage circuit when water or a damp item (toilet paper.... ) contact the probe for each level. A single probe at the bottom of the tank provides the return path. So imagine a piece of tp hanging on the probe down to the bottom of the tank where there is always a skim of water over the return probe. Completes the circuit so depending on which probe has tp on it will give the false reading. Same for soap, food particles that get glued together on the grey tank. Best solution is calgon to soften the water and make the inside of the tank slippery. Then lots of rinsing as in fill the tank above 2/3 level and dump. Black tank rinse helps but it does not fix. Lots of rinsing and never let the tank be totally waterless. We use calgon and regular laundry soap. You will get false readings with the soap because of the soap suds and bubbles. Let the tank sit a couple hours it will read correctly then

Just my 1/2 of opinion and thoughts

RoadrunnerII

[PlayersZ28]

The tanks sensors in waste tanks are at best a guess of what's in there. I can fluch my black tank for hours and get it to read E, use it a few times and it'll be @ 2/3 and it'll stay there until I dump after two weeks of boondocking.

If you really want to know what you have in them then you need an exterior sensor like SeeLevel.

[Motodad]

Thanks fellas. I have an older toy hauler ( won’t mention make on this site ) that has proved to be the most accurate sensors in a rig that I’ve ever had.
Not very concerned, as I dump and treat as needed. Was just curious as to this being common.
Thanks again and enjoy the day.

[Jim Davis]

I've given up on the sensors. For the Black Tank I use a flashlight and look down the "Glory Hole". At least on my Hummingbird I can see the level. I dump the Gray at the same time. So far so good.

[Marine71-76]

Well ours quit working completely after we had an issue with the USB plugs in the bedroom - will not use them again. Several suggestions that have been made to us:

1. After dumping black tank, make sure you put in water - it was recommended 10% so for a 60 gallon a minimum of 6 gallons. We usually put in a little more.

2. If your sensors are not working to your satisfaction, purchase a large bag of ice & dump it down the toilet hole and then drive. The ice will hit against the sides & help loosen anything now sticking. How long should you drive? Was told 1 hour minimum. Yes we have tried the ice & it seemed to help.

As far as dawn soap - make sure to use the blue only - even for washing dishes.

[jasonmiddlebrooks]

Originally Posted by Marine71-76

As far as dawn soap - make sure to use the blue only - even for washing dishes.

Why blue only?

[Marine71-76]

Originally Posted by jasonmiddlebrooks

Why blue only?

We were told there are fragrances used in the others that could impact the chemicals used in the holding tanks.