tank sensor accuracy

[Rmack1]

I'm a newbie, and after my fifth trip, I've noticed that my water tank sensors are different. At least I think they are.

What I mean is; the waste tanks tend to read high. In other words, they read being full a good deal before they actually are. On the other hand, the potable water tank seems to read low, just like a car fuel gauge. It reads low, indeed empty, a bit before actually being empty.

This would sort of make sense, so that the hapless RV owner would be prompted to correct the situation as it was developing, rather than wait until it was too late. I just want to make sure this is what I'm seeing.

I'm sure my black tank reading full just after I dumped it, RIGHT after doing a three day full sensor cleaning flush, with lots of fresh water is due to a chunk of toilet paper (marine only!) that has got stuck on the sensors.

Just shoot me now!

[DE88ROX]

Harvey51 wrote:
I worried about tank levels until someone here pointed out that the waste tanks are larger than the fresh water tank, so they cannot fill up between freshwater fill ups. I put a clear plastic tube over the freshwater drain so I can see the level in the tube. I know when to fill up - and make a point of dumping at the same time.

I have 90 Gal. fresh and 35 gal black and 35 gal gray.

[jnharley]

We have the Sea Level gauges and still the galley tank does not read correctly. It is narrow in height and because of that, it is difficult to get an accurate reading. The others work fine though.

[Harvey51]

I worried about tank levels until someone here pointed out that the waste tanks are larger than the fresh water tank, so they cannot fill up between freshwater fill ups. I put a clear plastic tube over the freshwater drain so I can see the level in the tube. I know when to fill up - and make a point of dumping at the same time.

[opnspaces]

I know I'm going to hate myself for saying this, but my sensors are almost always correct. And yes they are the standard bolt through the side of the tank sensors. Well once in a while the black sensor sometimes sticks at 1/3 but I've never had a false 2/3 or F reading that a fill and drain didn't take care of. I could probably do the same on the 1/3 sensor, but that one just doesn't bother me enough to want to waste the water to clean it.

To answer the original post though, yes the stock sensors are fairly inaccurate.

[DE88ROX]

Well after 1 full season of using these probes, I will give them an A+.

Aside from sticking a yard stick down into the black tank to measure, they seem to be pretty accurate. My black tank was always showing 2/3 full since I emptied it on my 2nd trip. (trailer was brand new)

Now when I dump my tanks the gauges read empty, just like they should.

[DE88ROX]

I bought 2 sets of these for my TT last fall. 1 for black tank and 1 for grey. Purchased the TT brand new and after my 3rd trip out I was already getting false readings and I know it was empty. TT came with a black tank rinse system already installed!! These are supposed to cure that.

I don't know how well they work as I have yet to install them. Thats one of the first things I plan on doing when I get it out of storage.

[reinita]

Try the ice method. Throw a bag of ice down the toilet after you dump. Theory is it'll clean the sensors while you drive. It's not perfect by any means, but it helps and we have used it with pretty good success.
As gross as it sounds, just looking down the toilet throughout your trip is really the best way to know. Trust me, you will know when it's time.
Six of us have camped for a week without having to dump. That's the longest we have gone. That was two adults, three teens and a little guy.
We conserved water like when we were tent camping and encouraged the kids to use the campground toilets if they were out and about (but didn't make it a requirement).
Happy camping!

[wbrown62]

The term "tank sensor accuracy" is an oxymoron. With time you will intuitively know when they are nearing capacity.

[wingtraveler]

My waste sensors work well the fresh water usually doesn't. After time you just kinda have a feel for what you have. As a full timer you also kind of use up the spaces pretty much the same week after week so we basically dump the same time each week.

[wa8yxm]

The standard waste tank sensor is about as complex as a nail in the tank, in fact it IS a nail in the tank. They work once (When new) and may work once again if you do some SERIOUS cleaning.

Now, there are alternatives: Horst Miracle probes. are designed so as to, in theory, work better, Some folks have reported good results, I have not yet tested them (Planned this summer upgrade)

SEE Level sensors WORK, period, less they come off the tank.

But the standard sensors.. A joke.

[rreynold51]

X4 on the seelevel gauges...but we do the same thing we use to anyhow....we shine a flashlight down to verify! If we are out for a long time we use our gray tank water to flush the toilet also....recycle! Even includes some dish soap to keep the black tank stuff from sticking!!!

[1775]

x3 on the SeeLevel gauges. The usual gauges installed especially in the black tank will generally give false readings and show full when it is not even half full. Anything in the tank that gets stuck on them will turn them on. These sensors are just switches that turn on when water connects the bottom connection to a sensor above. Toilet paper or whatever in the tank that is caught above will turn on the switch. I get fairly accurate readings on all gauges except the black tank. At some point I will make the change to the external SeeLevel system.

[WandaLust2]

Our gauges don't work either, and we tried the useless suggestion of adding water softener mixed with detergent etc. The only accurate gauge is the fresh water tank one. 🙂

We look down the toilet to see when it needs dumping and just guess with the gray water.

[rjsurfer]

The last time my black tank registered correctly was the second day of our first camping trip 6 years ago.

Ron W.