Black tank sensor not working

[On the go]

Our black tank reads almost full even when just emptied. The sensor must be blocked. What is the best way to get it to read correctly? We haven't had this problem before. Any ideas appreciated.
Thanks in advance

On the go

[jesilvas]

What kind of trailer? What kind of sensors?

[the_vfox]

Those sensors are basically worthless after a while. To try and keep it clean, one thing you might try, and it will take more than once, is when you are heading out, put dry dishwasher soap and about 5 to 10 gallons of water in your black tank. When you get to your next site, fill it up with water and drain. Repeat as needed. I quit using the black water sensor.

[tuffr2]

The black tank sensor in my trailer still works fine. The reason is I use ice when I move. Just buy a bag of ice at the campground gate. Dump it down the toliet then drive to your next destination. If parked for a longer time I let the 'black tank flush' system run for 15 - 20 minutes.

You can keep the sensors working if you focus on keeping the black tank flushed.

[On the go]

It's 2014 Alfa Gold by Lifestyle & have only used it a few times. Not sure about the brand of sensor, haven't had a chance to check.
Thanks for your reply.

[On the go]

Originally Posted by the_vfox

Those sensors are basically worthless after a while. To try and keep it clean, one thing you might try, and it will take more than once, is when you are heading out, put dry dishwasher soap and about 5 to 10 gallons of water in your black tank. When you get to your next site, fill it up with water and drain. Repeat as needed. I quit using the black water sensor.

My husband used some dawn dish detergent and that didn't work so we may try your suggestion, thanks for your input
On the go

[On the go]

Originally Posted by tuffr2

The black tank sensor in my trailer still works fine. The reason is I use ice when I move. Just buy a bag of ice at the campground gate. Dump it down the toliet then drive to your next destination. If parked for a longer time I let the 'black tank flush' system run for 15 - 20 minutes.

You can keep the sensors working if you focus on keeping the black tank flushed.

We will try the ice also, thanks for your advice
On the go

[Mkccowboy]

Originally Posted by the_vfox

Those sensors are basically worthless after a while. To try and keep it clean, one thing you might try, and it will take more than once, is when you are heading out, put dry dishwasher soap and about 5 to 10 gallons of water in your black tank. When you get to your next site, fill it up with water and drain. Repeat as needed. I quit using the black water sensor.

I use a similar method I picked up on one of the rv forums a few years ago that instead of dry dishwasher soap, You mix a cup of dry laundry soap with a few ounces of liquid fabric softener dumped in the toilet. Fill black tank with water and drive home with mixture. Works great, and have not had any black tank sensor miss readings since. The fabric softener leaves a slick surface on tank walls and when I use the black tank flush the liquid is basically clear pretty quickly. I use a clear elbow on dump outlet and difference is noticeable. 😄

[sam60]

I've heard clean water and rock salt while in motion to destination.

[ralphie]

I've never been able to rely on black tank sensors in any RV I've owned. I consider myself fortunate if the fresh and gray water sensors work

[jaybe]

I have been told (but never stuck my head in there to check) that the main culprit with black tank sensors is T.P that sticks to them and goofs up their ability to work correctly. While I have never tried any of the above mentioned solutions, I would lean toward the soap and/or fabric softener as a way to dissolve any offending paper. Seems like ice might be hit or miss.
FWIW.

[09 harley]

The only solution is to change to sensors that monitor thru the tank not from inside with sensors that always fail. Go with the See Level system by Garnet Industries and you will be happy. This system should be standard on all RV's not just some.

[Half Dimes]

What finally worked for us was putting several gallons of water in the black tank, tossing in one of those dishwasher 'pellets', then driving to where ever we're going.

[luckyd]

A huge culprit is Calcium. There are a lot of areas with hard water.
Calcium coats the sensors.

Dump black tank.
Mix 5 gallons of HOT water and Calgon.
Calgon is a water softener.
Dump down toilet.
Add 1 cup laundry detergent.
Let sit overnight.
In the morning, fill to 3/4 full.
Drive to next destination.
Flush.

Have used this for years, every few months.
Never a problem with the sensors.