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Holding tank gages

okiefatman
Explorer
Explorer
I have a 2k16 Sierra 355re my black gage reads full all the time and my gray & galley tank gages read 1/3 all the time. No matter what level is in the tanks they read the same all the time. Fresh water tank and battery gage works ok. Any suggestions?
10 REPLIES 10

ScottG
Nomad
Nomad
We have a black tank flusher but it only does so much.
About twice a year I use a home-made flushing wand to really clean it out.
The wand is a 30" piece of 1/2" PVC with a 3/4" thread on one end (for the hose) and a cap on the other end with two 3/16" holes drilled in it. I use and old washing machine supply line to attach it to a garden hose.
The force of the water coming through those tiny holes creates a powerful jet that rips anything loose that is stuck in the tank. Because the pipe is small, I can aim it upward and all around the inside of the tank. I hold it on the sensors (wife watches panel) and it cleans them in seconds.
I store the whole thing in a larger piece of ABS.

md_procouple
Explorer
Explorer
We have had the same issue... found this to work a little... before we leave home or C/G, We partially fill, tanks, then add 1/2 bottle of Dawn dish detergent through the shower and Kitchen sink, drive to your destination, dump tank. That worked for us we do that a couple of times per season. Worked on Both Black and Gray water tanks, and doesn't harm the seals on the tank. Good Luck and Happy Camping !!
Vickie, Me, and "Scruffy" our dog make THREE
:W

js6343js6343
Explorer
Explorer
It's a scam that works for your first trip, then never again thereafter.
2011 Keystone Sprinter 311BHS
2004 Suburban 2500 8.1L 4.10
Reese dual cam WDH
Tekonsha Prodigy 2

bad99ram
Explorer
Explorer
B.O. Plenty wrote:
They are never going to work correctly. I haven't looked at mine in years. When the toilet burps because the tank is full and blocks the vent, it's time to dump. When the sink or shower backs up same thing. I often leave my gray tank valves open. Never have a problem.

B.O.


X2

B_O__Plenty
Explorer II
Explorer II
They are never going to work correctly. I haven't looked at mine in years. When the toilet burps because the tank is full and blocks the vent, it's time to dump. When the sink or shower backs up same thing. I often leave my gray tank valves open. Never have a problem.

B.O.
Former Ram/Cummins owner
2015 Silverado 3500 D/A DRW
Yup I'm a fanboy!
2016 Cedar Creek 36CKTS

valhalla360
Nomad III
Nomad III
It basically an unavoidable issue (or at least not worth the hassle to keep them working).

Basically, there are metal electrodes set at different levels in the tanks. The idea is when the fluid level reaches the height of the electrode, the fluid completes a circuit and that is connected to the lights on the readout.

The problem is as crud builds up on the sides of the tank, there is enough moisture that it bridges the gap to the upper sensors completing the circuit even though the tank is not full to that level.

You can spend a lot of time and effort trying to clean them thru various methods with varying degrees of success but the minute you stop the issue will return. Or you can get a rough estimate of how long you can go on tanks and just drain beforehand.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

lanerd
Explorer II
Explorer II
Do you have a black tank rinse device? If yes, then on you next day to travel, empty both tanks and with the rinse device, put about 5 gallons of new water into the tank (use sink faucets for gray tank) and then put into each tank 1 cup of liquid laundry detergent (and with the Calgon if so desired) and travel to your next destination. The sloshing of the soapy water in the tank will act as an agitator and remove all debris from the sensors. Once at your destination, empty both tanks and put more clean water back in and use the system as you normally would. Repeat this procedure every time you travel and I assure you that your tanks/sensors will function as designed.

Ron
Ron & Sandie
2013 Tiffin Phaeton 42LH Cummins ISL 400hp
Toad: 2011 GMC Terrain SLT2
Tow Bar: Sterling AT
Toad Brakes: Unified by U.S. Gear
TPMS: Pressure Pro
Member of: GS, FMCA, Allegro


RETIRED!! How sweet it is....

jake2250
Explorer
Explorer
H20, Lots of H20. We use Calgon softener in the black and make sure (when I have the time) to flush out the gray tank with allot of water. It seems to keep the sensors clean and working. Just confirm you are starting with an empty black tank first, Shine a light down to toilet and see if you can see the bottom of the tank.
I have also installed a black tank rinser. Again, when I have the time I hook it up and let it do its magic!
You can also try Calgon in the gray tank. just pour it down the sinks.

the_bear_II
Explorer
Explorer
Common problem... only temporary fixes unless you replace the sensors with better aftermarket units. Basically gunk builds up and confuses the sensors. You can try some of the cleaning methods you'll find if you do a search.

We have learned that we can go for about 7 days before we need to dump the tanks. On our old TT with smaller tanks it was 4 days.

If we have guests then it drops to 5-6 days.

2oldman
Explorer
Explorer
Same post
"If I'm wearing long pants, I'm too far north" - 2oldman