Black water tank always shows 3/4 full

[CaptainVideo]

Black water tank always shows 3/4 full. We have a one-year-old white hawk which we have only used four or five times. We are always careful about dumping dishwater down the toilet and run lots of liquid through the toilet but we noticed that the indicator lights always show 3/4 full. Any suggestions for how to solve this problem?

[Colorado]

A lot of people have the same issues with the sensors, you’re not alone. If your camper was sitting for a long time there may be dried material on the sensors, that’s what happened to ours. I filled the tank until the full sensor JUST started to register the water, plenty of Dawn and several drop ins. I let it sit for several days then a LONG DRIVE through town to get the solution to slosh inside the tank. I did the same with the grey tank. The following is the routine I do now...

There’s probably tissue residue on the sensors. I add 5-10 gallons of water, 1 cup Dawn dish soap and a Commando drop in to the black tank after It’s been empty. I plan ahead when it’s time to dump the tank, I fill it FULL with a hose and go for a drive around town...lots of turns, stopping and starts THEN I dump. It’s been working great so far.

[Jagiven]

The problem is the sensor design. Basically it is a nail that stick maybe 3/4 of an inch into the tank. Guess what, that sensor probe collects "stuff" on it, and completes the circuit. Generally speaking, most people just use a flashlight and looks down the toilet to get an idea how full the tank is. This is a good practice to make sure you have enough water in the tank.

You can replace the sensors. There is one that is similar to the existing sensor, but they have a little cap over them so stuff does not build up directly on the probe (sorry forgot the name). Then there is another that is called Sea Gauge, that uses a different technology and are very accurate, and tend not to give false readings.

I tend to just live with it. But when the gauges start getting flaky I may add about a cup of liquid fabric softener (can use water softener crystals too) to about 4 gallons of water, and dump about half into each tank after dumping. I also add a few more gallons of water to the black tank. The softener changes the surface tension of the water, so it can penetrate into the stuff, and loosen it up. The sloshing motion while driving washes the walls down.

You should test your TP, to make sure it is RV suitable. Take one or two clean sheets. place them in a small jar with some water. I do not recall the times anymore. But lightly shake it up for a few seconds, and let it sit for 30 minutes. After 30 minutes, the paper should be dissolve in the water. If it looks anything like TP, find a different brand.

After you dump, always fill the Black tank with clear water, about 10% of the tanks volume. So if you have a 40 gallon black tank, put in 4 gallons of water back in right away. Never leave the tank dry unless it is for winter storage. Water, and lots of it, is your friend.

[crl]

We too have a White Hawk and the black water tank almost always reads 3/4. I am extremely diligent in clean outs after each trip. If the dump station line allow I will flush with my black water flush and the fill till sensor says full two to three times. When I get finished my sensor will read empty. Buy the time I get back on it is reading 3/4 again. We have tried all the published remedies and nothing has seem to help.

I finally stopped stressing about it. If my DW and I don’t have sewer hook ups, we can go at least 5 days with room to spare. If you find a magic pill that fixes the problem let us know. As said, we have learned to manage without it.

Good Luck!

[CaptainVideo]

Thanks. We learned a LOT from your post & have our homework.

[TCNashville]

Try this. It's worked for me for 5 years now. Use the liquid Calgon instead of the powdered.
https://uniquecampingmarine.com/blog...the-geo-method

[Scott_Trailer_Newbe]

Our trailer always does this. The solution is the black tank cleaning feature (if your trailer has this). After spraying it down it always reads correctly, but I must do this on every camping trip or it will read 3/4 full on the next trip even though I know its empty.

[cekkk]

Not to worry. I think the only subject that rivals this one would be will my F-150 pull my 36' TT. There are many suggestions on how to deal with the black water thanking what's in Decatur, but as far as I'm concerned the best solution is a flashlight and a quick look down the toilet into the tank. it will never appear full when it's empty nor will it appear empty when it is full.

[RetiredOne]

My black tank sensors started to act up, so when I came home this past weekend, after I dumped in the campground, I used my black tank flush to fill the tank like 3/4 of the way, added PineSol and Dawn, and let it swish around on the ride home.

When I got home, I hooked up my drain line to the sewer cleanout, and drained it all... Now, my sensor reads empty.

[travelingjw]

We have a 2017 Whitehawk. We've tried most of the above suggestions, sometimes they work, sometimes they don't. Calgon and Dawn seem to work the best for us but the one thing that does work every time is when we move from one campground to the next; we fill about 1/3 full and let the water swish around on the drive. When we arrive we dump the black tank as soon as we are level. I don't remember the OP of this method but he nicknamed it the "sloshinator"! Frankly, after 3 years of camping we always have an idea of when the tank is getting full and use a flashlight to check.

[Cavie]

When the toilet burps flush the tank.

[Rambling Drabek’s]

I googled Sea gauge and couldn’t find anything. I did find one called See level, is that the one you are referring to? The See level looks like a good system. We have the same problem with our tanks as well, I saw a video where a guy put a couple bags of ice in his tank and drove around.

[norty1]

Originally Posted by Rambling Drabek’s

I googled Sea gauge and couldn’t find anything. I did find one called See level, is that the one you are referring to?

Here is the link if anyone wants to look! https://www.garnetinstruments.com/rv-shop/

[RAurand]

Some folks use these. Just make sure you mount them correctly!

https://www.etrailer.com/RV-Sewer/Va.../T21301VP.html

[m2bandit]

We just don't pay any attention to ours. Gray fills first anyway.
It has nothing to do with what's left in the tank or the TP we use. (Charmin ultra soft is fine btw)
One flush it can be on E, the next flush 2/3. Our sensors must be right next to the toilet.
A couple times I verified it was empty after dumping because of the sensor. Now I don't worry about it.

[jloco]

My BT meter is still accurate on my 2016.. I do dump, flush, fill, dump.. seems to work.. I'm connected to sewerage at my site so it's easy for me to do..

[Marmot]

Originally Posted by CaptainVideo

Black water tank always shows 3/4 full. We have a one-year-old white hawk which we have only used four or five times. We are always careful about dumping dishwater down the toilet and run lots of liquid through the toilet but we noticed that the indicator lights always show 3/4 full. Any suggestions for how to solve this problem?

The only surefire way is to buy an RV tank cleaning wand. I use the Camco RV Flexible Swivel Stik. Dump the tank, squirt some Dawn or LA Awesome in there, then run the Stik down a few inches and turn it on full. Let it run for 10 minutes then squirt some more cleaner in and again run for 10 minutes. That should do it. Use the Stik every time you dump the tank, for about 2 minutes, to prevent future problems.

[Hollander Mutthaulers]

Inaccurate gauges don't bother us any more. You just kind of get a feeling. The worst part is knowing that in yet one more way Jayco - and others - has put in a feature that they know doesn't really work. Why do something when you know it just plain doesn't do any good? Perhaps sometime I'll be curious enough about Valterra miracle probes to give them a try. And that's the positive about RVs - they are made just crappy enough to allow and encourage owners to customize them and make them "better than new" and that's half the fun.

[JFlightRisk]

We flush the black with a wand every time also, and those are still working after 8 years. The gray tank's been stuck on 1/3 for the first time ever, this summer. So I ordered the Horst sensors for the gray tank. They arrived yesterday, went out to check the level before I crawled underneath with the new ones. You guessed it...shows empty! Go figure!

[CaptainVideo]

Is there a reason everyone suggests Dawn, which I don’t have, instead of Palmolive which I do have?