Black & Grey tank readings

I had this problem awhile back. The solution I found was to take some liquid diswasher detergent. I bought Dollar General brand. Put a cup of detergent and about five gallons of warm or hot water in tanks. I do this when going to local state park. About 30 minutes of driving. Dump tanks when I get to campground. The first time I did it it took two cleanings, but sensors worked fine again.

RV tank sensors usually work if the tanks are clean, unless there is a malfunction between the sensor and the display. We just had our tanks cleaned by a dealer with the nationwide service company AllPro Water Flow. They used a pressure washer to spray the inside of the black and gray tanks. We haven't had any problems with the tank readings, but since our coach is now 5 years old, we figured it was time for a thorough cleaning. Comments above about the Dawn/Calgon and Happy Camper are spot on. Also, use lots of water in the toilet.

I'm on my 4th camper, 3 TT's and now 1 5er. All my sensors, on all my tanks: fresh water, black and grey and grey, have always worked and worked well for me. I do not depend on the sensors, but I check them often anyway, and they do a good job and being a good gauge and my estimation is pretty close.

But I am animent about keeping them clean to, and steps are very simple ... very simple...

Dump your tanks when leaving your campsite. After dumping, add 4 or 5 gallons of water to the black, grey, and grey tank. Then a half cup of Dawn dishwashing liquid and drive to your next destination. If you have the opportunity, drain the tanks again. If not, just use as normal.

The dawn will clean the inside, driving on the road will cause the water and dawn to pulverize the inside of the tanks. The beating of the water will wash off the sensors, and they never get gunk caught on them.... which is what causes them to malfunction.

Plus, you never have smells in your tanks this way.

Fresh water is the same. Just travel with a few gallons in your fresh water tank. The pounding of the water will keep the sensors clean.

FYI, the cleaner you can keep your black tank, the better everything works. I do work agressively dumping the black tank, back-flushing the grey tank into the black to help clean (a LOT) of stuff out that never drains the first time, using the black tank flusher every time I dump (which I can hook up to my fresh water tank in the camper and do not have to depend on campsite dump stations), and also use a toilet wand inside the black tank down the toilet hole every now and then. Combined with the beating of the water when on the road, black tank stays clean.

A lot of folks don't go to these lengths with their black tank. Maybe I'm just really anal retentive when it comes to the black tank. ;) But my sensors always work.

Even the external sensors don't always work.

Use lots of water.

If a flush kit is installed, dump with it on, refill for 5 minutes, dump again, and then repeat a 3rd time.

joebedford wrote:
Never trust them.

Or, could be worst, showing empty when it is actually flow -- then overflows.

Never trust them.

The solution maybe a simple thorough cleaning and flushing once after each camping trip.

It seems a quick dump leaves a lot of residual sludge inside that can cling of get stuck in floats and sensors.

Detergents and double dose of double-dose of aqua-chem on both gray and black tanks will do the job.

Sometimes it take a few more flushing operations to finally see a clean and clear water flowing down the pipes.

How long has it been since you dumped? Sometimes you just have to wait a while for the sensors to dry out inside the tanks. Mine used to do the same, and usually waiting was the answer.

I've never had any problems with my sensors indicating correct levels. I thoroughly flush my tanks before departing a campground but while at the campground, the dump valves are always closed except when I'm emptying the tanks. A couple of times a year, I use a wand down through the toilet to clean off anything sticking to the walls. I use Happy Campers Holding Tank Treatment and added a flush-out to the grey tank. I also use and prefre Charmin Ultra toilet tissue and have no issues with it. I've been RVing for over 40 years.

Below is a link to a dealer's website where you can learn about the Happy Campers treatment.
https://www.happycampers.store/

Either exterior sensors like seelevel, or clean the tanks from the inside. Grey tank you can dump in some Dawn or other detergent. I'll sometimes squirt some down the sink if I know I'll be dumping at my next destination. The drive gets it all stirred up and clean(ish). Black tank you can also install a flusher, or use a wand down the toilet if the black tank is right below the toilet.

I've had good luck with lots of water, and some Dawn in the tanks when I know I'm dumping at the end of the day's drive.