Tank Sensor theory (poll)

[Huntindog]

It seems that most here have issues with their tank sensors being unreliable.
My experience has been quite the opposite. I have rarely had a problem.
Most all of my trips have me towing home to dump, at least 150 miles, with some bumpy dirt roads at the start.
I think that the agitation stirs things up, dissolving the TP so that it can't foul the sensors.
The few times I have had a false reading was when I had a rare short tow home. (20-25 miles)

I get the impression from reading here that most use the dump station at the campground.

I would like to hear mainly from those without sensor problems, just what you are doing? I will of course assume that everyone is using TP that will dissolve when swished around in water.

[babies_dadeo]

Sensors on all the trailers I have owned were hit and miss. I have found that the black tank is the only issue I have. I have my current trailer on a full service site 90% of the time, but always let the tanks get pretty full prior to dumping. I did have it get stuck showing full once, but I filled it with fresh water, and went for a 1 hour drive on some country roads... seemed to work better after that.

[dodge_guy]

No problems for me! The only thing i don't like is the tanks that are set up to read 1/3's. they read 2/3's until it reads full. Very bad design! My first 2 TT's read in 1/4's and were great!

Any way, no tank sensor problems for me!

[wmoses]

ANewTraveler wrote:
Question: In most RV's can the "bottom' of the tanks be seen from under side of the trailer, camper, MH, or 5th wheel? i.e. if I slide up under the MH can I see the bottom of the tanks? - I'm working on something here...

Not if the RV has an enclosed underbelly.

[Lantley]

I never bother with the sensors anymore. After 4 showers or so the grey tank needs to be dumped. If I need a little more grey capacity I will close the outlet with a 3rd gate valve and open both tanks and let the additional grey water drain into the black tank.
In short I never check the gauges I don't know if they are accurate or not because I just don't use them any more.
If the grey gets full the shower drain will back up. If the black gets full you'll know the toilet simply won't flush, however I have never camped long enough to fill my black tank. 4 of us can easily go a week without filling the black tank

[ANewTraveler]

Question: In most RV's can the "bottom' of the tanks be seen from under side of the trailer, camper, MH, or 5th wheel? i.e. if I slide up under the MH can I see the bottom of the tanks? - I'm working on something here...

[thib2722]

I have a back flush and a tornado rinser and my sensors are never accurate. We used bio treatments in the tanks, and that keeps the smell out but it doesn't fix the sensors.

We have had several TTs and never had good luck with sensors.

[ktmrfs]

sensors are basically a switch providing a current path to ground. to do that they need a reasonably low resistance, which is what normal water etc. provides. BUT let a film of crud build up on them and it's like a tank of water, low enough resistance to give a "false" trigger the LED. detergents etc. will help keep the film from building up. Probes like the Horst probes have a teflon sleave and for black a shroud over the top. The teflon sleeve is a very high resistance insulator and is long enough that it takes lots of crude to make a low resistance path, and teflon is slipery enough to minimize buildup.

However, non of these are perfect, soap suds in the grey can give a false trigger, debris likewise.

the circuit is very simple, but a compromise. It could be much less sensitve to this stuff, but then would draw much more current ALL the time when a LED is on, not something you want when dry camping.

Seems like those that are able to keep the tanks reasonably clean have the best luck. Detergents and water softeners are your friend here. I prefer dishwasher or HE laundry detergents, less suds, which can give a false trigger, but use whatever you like and is handy. Water softener keeps the film from building up in areas with hard water.

and try not to let the scum etc. get dried onto the sensor, much harder to get it off then, and just about impossible to get in and scrub it off.

[5rvers]

Met a nice old-timer a few camp trips ago he said use half a cup of dawn and 4 gallons of water I each tank and it will keep the sensors clean. Just started doing it and hope it keeps my sensors working for a long time.

[DB2BRMI]

Never look at the gauges anymore. Not worth the time messing with them. At snowbird camp (no sewer hookup) we dump both grey tanks every ten days (29 gal. each) with blue boy and dump the black every 14 days when we move (required to move to new site every 14 days). Yes we conserve our water use. Not flying on instruments; flying visual. Blue boy is used for grey only.
DRB

[ReferDog]

A joke have 3 of them non 1/2 way accurate

[The_Painting_Te]

Our sensors have worked for years. I rinse the black tank every time I dump, and I almost never carry water so the fresh water tank gauge is never an issue. To keep the gray and black tanks clean from year to year (we snowbird only) on our 2nd to last day on the road I fill both 1/2 way with dishwashing detergent (no suds); then dump. On our last day on the road I fill 1/2 with water; drive to our last overnight; then dump before leaving for home. Both tanks are pretty spotless and gauges work fine. Camp on!

[Old-Biscuit]

Doug33 wrote:

jerem0621 wrote:
I just use the burp theory of tank fullness measurement.

say what??

'Burp' method is an old tried and true method of knowing when to dump black tank.

Toilet 'burps' when flushing......level is high enough to partially block vent line.......therefore it burps thru toilet. TIME TO DUMP BLACK

Sink/shower drain starts to slow down....TIME TO DUMP GREY

Water pump goes 'burruppppp'....should have refilled fresh water tank.

I don't even look at monitor panel. Don't care if they work or not.
I know/learn how long before needing to dump...then I dump.

Just side note:.........don't care if 'clocks' work either

[Huntindog]

thib2722 wrote:
I've had several trailers, and none of the stupid sensors every worked as advertised. I back flush and have a tornado flusher, and it simply doesn't matter. By design, they are stupid.

Let's stick a piece of screw in a tank filled with solids and tissue and see if anything will hang up on it??? That's poor engineering. Of course,******is gonna hang up on it. If a piece of tissue sticks to the top sensor (full) and dries on there, you're done in. Unless you fill the tank to the very top and let it soak forever, that paper is likely never coming off.

With all the brainiacs in the engineering world, it seems one would fine a more reliable yet affordable solution. We just have learned from experience that we need to dump about every five days.

We can actually sort of tell how full the black tank is by the sound of the water when we flush. It changes pitch as it gets full.

So what else do you do? Do you use TP that will dissolve? Do you dump at the campground?
Do you tow with the tanks full? How far?
Do you use any tank treatment? What type?

These are the questions that this poll is attempting to address. There are those, including myself that have had very good success with the sensors. There has to be a reason or reasons that some have trouble, and others do not.

[thib2722]

I've had several trailers, and none of the stupid sensors every worked as advertised. I back flush and have a tornado flusher, and it simply doesn't matter. By design, they are stupid.

Let's stick a piece of screw in a tank filled with solids and tissue and see if anything will hang up on it??? That's poor engineering. Of course,******is gonna hang up on it. If a piece of tissue sticks to the top sensor (full) and dries on there, you're done in. Unless you fill the tank to the very top and let it soak forever, that paper is likely never coming off.

With all the brainiacs in the engineering world, it seems one would fine a more reliable yet affordable solution. We just have learned from experience that we need to dump about every five days.

We can actually sort of tell how full the black tank is by the sound of the water when we flush. It changes pitch as it gets full.