Community Forums

Doodle Mom · 05-20-2022, 08:00 AM

The black tank still shows full after a dump. We filled it with water and got more stuff out but it still shows full. We’re figuring there is something stuck on the sensor but what’s the best way to clean it out? Do they make like a “douche” for the black tank?
Thanks!

sploke · 05-20-2022, 08:33 AM

Quote:

Originally Posted by Doodle Mom

The black tank still shows full after a dump. We filled it with water and got more stuff out but it still shows full. We’re figuring there is something stuck on the sensor but what’s the best way to clean it out? Do they make like a “douche” for the black tank?
Thanks!

Fill it halfway with water, add a scoop of dishwasher detergent e.g. Cascade (NOT liquid dish soap like Dawn, you'll end up with a tank full of soap suds!) and drive around for a while, let it slosh around and break down the buildup, then drain it.

Bill Nourse · 05-20-2022, 09:03 AM

We were in Az. for the winter and all of the tanks were like this for 4 months. After we got home and the trailer set for 2 months the sensors are now showing empty again. From what I have read it is pretty common for the sensors to do this.

Sparky1 · 05-20-2022, 09:28 AM

add ice cubes & do a zig zag they will help clean off sensors..

ArtJoyce · 05-20-2022, 11:00 AM

Yep it happens to all of us from time to time.

Tdave · 05-20-2022, 11:03 AM

Quote:

Originally Posted by Doodle Mom

The black tank still shows full after a dump. We filled it with water and got more stuff out but it still shows full.

That must have been one huge dump!

Typical issue, see answers above.

amosnandy · 05-20-2022, 11:11 AM

Quote:

Originally Posted by Lamont

add ice cubes & do a zig zag they will help clean off sensors..

Ha ha ha. Old wives tale that ice cubes actually work. I've seen the video of tests on this. Waste of time and perfectly good ice.

Yes, cascade dishwashing liquid. I spend 4-6 months on each end, with 6-7 days of travel twice a year. I put most of a bottle of cascade in each tank. I used to put 10 gallons of water in but realized I go most of that 7 days without dumping. Clean and the sensors work great......for a couple of months.

I summer in a park with seasonal camping. Most of these rigs haven't moved in 10 years or more.

The black tank flush works well too. Never figured out why manufacturers put a sprayer in the black tank and never in the grey. What would it add for cost? $12?

Sparky1 · 05-20-2022, 11:29 AM

dont add sprayer PEOPLE FORGET AND OVER FLO THE BLACK TANK-HUGE MESS.

pddgm · 05-20-2022, 01:44 PM

I hook up my in tank cleaner before dumping, run for approximately 2 or 3 minutes and then pull the lever.. On my other rig, I used the down to toilet spray wand and it didn't work very well. I put a 1/2 cup clothes washing soap once a month or so. None of it seems to work that well cleaning sensors. They just gum up and it's a waste of good money putting them in.. Most smart people figure it out pretty quick with their tanks are full..

tuffr2 · 05-20-2022, 02:48 PM

I use my black tank flush for several minutes - as much as 15 minutes. I will kink the hose and then release it to add a bust of water pressure. That always works.

Oh, and use plenty of water when you flush.

DutchStarJez · 05-20-2022, 03:23 PM

The first time I used the Dawn/Calgon mix to clean my tanks in both the 5er and my class A I didn't notice any difference but a fellow camper told me it took a few times before he could tell it worked and so I kept trying and sure enough the readings became quite accurate. Not sure it will help in every situation but it has mine doing good.

TXTiger · 05-20-2022, 04:49 PM

Almost all tank sensors are inaccurate. A lot depends on the location of your sensors. Some are mounted inside the tank but many newer RV have the sensors glued onto the outside of the tanks. Sometimes they come partially unglued and are only hanging on, or the are completely off. Even if they are fully attached the side of the tank can be stained giving a false reading.

txcpl · 05-21-2022, 04:24 AM

spoke has the best answer. I use granular TSP, found. at any hardware store, instead of cascade. Use whatever you want, fill tank 1/2 to 2/3 full, then drive at least an hour before dumping.

bddadles · 05-21-2022, 08:11 AM

I personally do not pay attention to the sensor readings. I dump the black tank every Saturday and when I get ready to move after sitting for awhile I drop a laundry pod down the toilet, add a few gallons of water(I use the tank flusher) and move to the next location. Dump upon arrival. Sometimes do it a couple of moves in a row just because I can.