Black tank sensors show 2/3 full after dumping

Mlemonier · 08-06-2021, 06:56 PM

I am looking for solutions for a 5th wheel with two black tanks, both appear to have sensors showing 2/3 full after dumping. I do not know the capacity of the tanks or ideas as to how to clean the sensors effectively. I just parked the rig for two weeks. Suggestions?

**chuckster57** · 08-06-2021, 07:15 PM

Welcome to the forum

Lots of members will tell you to forget about using them. You can get a “tissue digester”, add 1/2 bottle to each tank. Then fill until you see water starting to come up the pipe at the toilet. Let it sit for 2-3 days and then drain.

Old Mustanger · 08-06-2021, 07:29 PM

Did you flush the tanks to make sure they emptied and are not blocked by TP?

John&Genny · 08-06-2021, 11:29 PM

Quote:

Originally Posted by Mlemonier

I am looking for solutions for a 5th wheel with two black tanks, both appear to have sensors showing 2/3 full after dumping. I do not know the capacity of the tanks or ideas as to how to clean the sensors effectively. I just parked the rig for two weeks. Suggestions?

As you can see from other responses, most black water tank sensors are worthless for the most part. Even after dumping and flushing the tanks, mine usually show 2/3rds full. So I usually wait until they start showing a full indication before I worry about dumping them again.

**flybouy** · 08-07-2021, 05:14 AM

Get a drink, maybe a sandwich and search "black tank sensors". Why the food and drink? Because the subject comes up often and you'll have plenty of reading to keep you busy.

Ken / Claudia · 08-07-2021, 05:35 AM

Of all the improvements I have seen in RVs the tank sensors have never improved in the RVs I have owned since the 70s. Welcome to Rving.

Mlemonier · 08-07-2021, 05:43 AM

Yes I did. From what I have been reading, it seems I am both using the wrong paper and flushing too frequently. My system has a black RV tank flush-that will be my next play. Thank you for taking the time to reply.

Mlemonier · 08-07-2021, 05:45 AM

Thank you for devoting your life to public service. Despite all the media sewage, we appreciate law enforcement and recognize the immense contribution your work makes to maintaining and promoting a civilized society. WE THANK YOU, AND ALL WHO SERVE.

Ken / Claudia · 08-07-2021, 05:58 AM

There are several of us on here, from me thank you for your kind comments.

**JRTJH** · 08-07-2021, 06:15 AM

Most "tank sensors" are nothing more than a nail on a rubber stopper that's installed into a hole in the tank. There are 4 of them at various levels inserted on one side of the tank.

The way it works is when there's "electrical resistance between a nail and ground, usually caused by the nail being wet" a signal is sent to the display unit and the red lights show how many sensors are "wet and conducting"....

Now, imagine the inside of a black tank with "poo solids and toilet paper floating around in it".... How long does it take before a "clump of poo and paper" gets stuck on the nail ????? Once that happens, if it's the 2/3 nail, your tank will read 2/3 full until that paper gets "wiped off the nail"... Chances of that happening are "slim to none"...

So, how "reliable" is a nail with poo on it ???? That's your "tank sensor mechanism".... IMHO, it's "guaranteed to malfunction the first time you "go, wipe, flush".....

Learn the sounds of your black tank. With some experience, you'll figure out the "gurgles and burps" and can tell from the sound of the flush how much is in the tank.... Relying on the black tank sounds is a significantly more precise way to tell how much is in the tank.....

That "pretty box mounted on the wall with all the lights and buttons: It's been there with dust on it since the first time our black tank was "really full" and it's read 2/3 since then whether it's empty, full, half full or ?????

dutchmensport · 08-07-2021, 07:52 AM

I've had 4 different campers and on all 4 campers I never had issues with the sensors working (mostly). The solution I found to keeping the sensors working is to completely dump the black tank. After dumping, rinsing, spraying, back flushing, or whatever you do, add about 5 - 10 gallons of water and take the camper on the road. It's just that simple.

The sloshing of the water inside the tank will clean the sensors. Now, the first time you dump, they may quit again if TP is caught on them. Nothing can prevent that. But again, when traveling, keep a small bit of water in the tanks, and it will pulverize as you drive, cleaning the sensors.

Now, if you want to get away from toilet paper completely, install a Bidet! We haven't used TP since February 2020, right before the TP shortage started. I'm glad we switched over to a Bidet, even installing one in the camper, and I don't think we've purchased more than 2 packages of TP since. We still keep TP on hand, but it's handy to blow noses and pick up doggie accidents. No paper goes down toilet, and the sensors in my Montana have worked great, ever since we gave up paper.

As I've found out from this and other forums, many folks think bidets are a horrible idea. But, there is no TP hanging around in my black tank at all!

**JRTJH** · 08-07-2021, 10:23 AM

Quote:

Originally Posted by dutchmensport

I've had 4 different campers and on all 4 campers I never had issues with the sensors working (mostly). The solution I found to keeping the sensors working is to completely dump the black tank. After dumping, rinsing, spraying, back flushing, or whatever you do, add about 5 - 10 gallons of water and take the camper on the road. It's just that simple.

The sloshing of the water inside the tank will clean the sensors. Now, the first time you dump, they may quit again if TP is caught on them. Nothing can prevent that. But again, when traveling, keep a small bit of water in the tanks, and it will pulverize as you drive, cleaning the sensors.

Now, if you want to get away from toilet paper completely, install a Bidet! We haven't used TP since February 2020, right before the TP shortage started. I'm glad we switched over to a Bidet, even installing one in the camper, and I don't think we've purchased more than 2 packages of TP since. We still keep TP on hand, but it's handy to blow noses and pick up doggie accidents. No paper goes down toilet, and the sensors in my Montana have worked great, ever since we gave up paper.

As I've found out from this and other forums, many folks think bidets are a horrible idea. But, there is no TP hanging around in my black tank at all!

Don't "shoot me for this" but I gotta ask: What's that brown smear on your hand towel ?????

dutchmensport · 08-07-2021, 03:40 PM

"brown smear" ... dedicated wash cloths for drying ... "down there." Only used for one purpose, nothing else, color coded for easy identification and for one type of use only. Works for us.

This got even more simple when we installed the washer and dryer in the camper.

**flybouy** · 08-07-2021, 04:23 PM

I don't consider myself "picky" or "tender" by any means. I've suffered a lot of pain, broken a lot of stuff (bones and such) and endured some "initiations" in my youth. The one thing I can tell you is that I'm not up for a cold water enema. To each their own.

**sourdough** · 08-07-2021, 04:54 PM

Quote:

Originally Posted by flybouy

I don't consider myself "picky" or "tender" by any means. I've suffered a lot of pain, broken a lot of stuff (bones and such) and endured some "initiations" in my youth. The one thing I can tell you is that I'm not up for a cold water enema. To each their own.

Like you, I'm far removed from "picky" or "tender", and, taught a lot of things back in the day to "survive" but one thing I hated.....and had few of other than "mandated" ones, are "cold water enemas" or having designated "brown wash cloths"....nope, ain't happenin. In the pot and that's all you got......

travelin texans · 08-07-2021, 08:16 PM

Toilet paper was designed to use on the tushy & drop in the toilet to disappear in a swirly. Nor does it go in a bucket next to the toilet, that's absolutely gross.
When I spray water down there it will be in the shower while cleaning all the other body parts, not spread eagle over the toilet. I also do not want an a## towel hanging next to my bath towel.
If you use septic safe tp & no more than 2 ply you should not have any issues with your black tank.......unless there are family members that need 1/2 a roll per job, if so give them the duty of curing the problems it causes.
With all the RVs I've owned in the past I've never had one that the sensors were worth wasting time & $$$ on. Yes there's all kinds of methods, magic elixirs, pods & drop ins that all might get it to be near accurate til after the next fill.

**sourdough** · 08-07-2021, 09:08 PM

Quote:

Originally Posted by travelin texans

Toilet paper was designed to use on the tushy & drop in the toilet to disappear in a swirly. Nor does it go in a bucket next to the toilet, that's absolutely gross.
When I spray water down there it will be in the shower while cleaning all the other body parts, not spread eagle over the toilet. I also do not want an a## towel hanging next to my bath towel.
If you use septic safe tp & no more than 2 ply you should not have any issues with your black tank.......unless there are family members that need 1/2 a roll per job, if so give them the duty of curing the problems it causes.
With all the RVs I've owned in the past I've never had one that the sensors were worth wasting time & $$$ on. Yes there's all kinds of methods, magic elixirs, pods & drop ins that all might get it to be near accurate til after the next fill.

^^^^And that's where the "burp" comes in.....never fails to notify.

JDDilly · 08-08-2021, 06:05 AM

I have had TTs and 5ers for close to 25 years. I gave up on the sensors long ago, just wait for the "burp" and dump the black tank. We have also used regular TP, just need to use enough water in the tank.

dutchmensport · 08-08-2021, 07:32 AM

And you all still wonder why the sensors don't work?

**JRTJH** · 08-08-2021, 08:26 AM

Quote:

Originally Posted by dutchmensport

And you all still wonder why the sensors don't work?

Nope, I know "exactly" why the sensors don't work. My "key to success" is understanding that and not relying on them for anything other than "excess weight under the trailer".... Since coming to that "awakening of reality" I've never had a problem with tank sensors....

To me, it's sort of like "flapping my arms"... I know it works for birds, but no matter how fast I flap, my feet stay firmly on the ground... Some things just aren't "meant to be"... In my "reality" one of those things is "RV tank sensors"... Haven't lost a minute's sleep since I started listening for the burp and treat "odor" (when required) and ignore "little lights in the hallway"...

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