After an 8,000 mi trip around the country, our holding tank fluid level gauge reads 2/3 full all the time. I cleaned it twice using a chemical holding tank cleaner, following the instructions to the letter. No change. The black water tank has done this to us a time or two over the years, but thats a simple fix with a flushing wand. I was wondering if anyone had any suggestion on a more effective cleaning method? Other than the drain, I don't see a way into the tank anywhere. Thanks in advance for any suggestions offered.Amended after original post. Problem is in the Gray water tank, not the black water/holding tank. Sorry about my mispost.

I have found the black tank flush connection and flushing wands to be helpful but not a complete flushing of the black tank. In addition, thorough black tank cleaning often requires at least two cycles of filling the tank and dumping and not uncommon 3-4 times before no debris is seen exiting. Then if still having problems with tank sensor, try filling the tank 1/2 to 2/3 full adding some water softener solution and some laundry soap, then go for a nice drive, preferably on hills and winding roads to slosh the mixture around and agitate.

You didn't mention it but I assume you are having a problem with the gray water tank sensors and not the black. I take care of that problem by removing the drain plug and inserting my homemade wand which fits into the small drain plug hole and blasting away with a stream of water aimed at the sensor locations in the tank. Of course one should also take the time to clean the rest of the tank also. Works every time.

If I really want to do a super clean job and most times the sensor will read correctly when done, I drag a garden hose through the door and go down through the toilet with the slide valve held open by the hose. Do not get distracted or you might have an overflow... I then close off the valve on the outside and let it fill 2 or 3 times and pull outside valve again. Sometimes I put some laundry soap down the bowl while I am doing this. I have a back-flush clear elbow on the outside, but the pipe goes across to the other side of the trailer and doesn't do much good.

ernie1 wrote:You didn't mention it but I assume you are having a problem with the gray water tank sensors and not the black. I take care of that problem by removing the drain plug and inserting my homemade wand which fits into the small drain plug hole and blasting away with a stream of water aimed at the sensor locations in the tank. Of course one should also take the time to clean the rest of the tank also. Works every time.You are correct, I miss posted by calling the problem tank the holding tank when it is indeed the gray water tank that is causing my problem, sorry about the confusion.I find no drain plug in the tank, only the main dump valve and it's a ways from the tank. It would be difficult to thread anything up into the tank. I might consider installing a plug in the bottom of the tank myself.

Holding tank cleaning | Good Sam Community

MEXICOWANDERER
Explorer
Jul 06, 2017
I had a friend who used to go to a local golf course, pickup a sack of ruined golf balls, dump then into the toilet, give them a nice curvy bumpy road ride, then drain the works. He used some brand of laundry detergent and let the golf balls rock & roll.

As he was bouncing up and down in hos seat he leaned over and said "Well whomever ruined those golf balls couldn't play worth ----"
SoundGuy
Explorer
Jul 05, 2017
I use Walex Elemonate in the grey tank and never have tank monitor issues. :B
rockhillmanor
Explorer II
Jul 05, 2017
In my manual that came with the MH regarding holding tanks it stated that something as simple as: "certain minerals found in well waters we get from CG's, our own wells and city water can foul the sensors."

Just using soaps etc will not remove the minerals from the sensors.

After reading this I started using the Thetford Sensor Cleaner that they suggested once a month. More if I was using different CG waters on my trips.

My sensors all work all the time! :C
1. Chems in black tank.
2. Qrt of lemon cleaner in gray tank often - to keep food stuffs, etc off sensors.
3. Thetford Sensor Cleaner once a month - to remove hard minerals from sensors.
Dusty_R
Explorer
Jul 05, 2017
Check out SeeLevel.
JDsdogs
Nomad II
Jul 05, 2017
ernie1 wrote:
You didn't mention it but I assume you are having a problem with the gray water tank sensors and not the black. I take care of that problem by removing the drain plug and inserting my homemade wand which fits into the small drain plug hole and blasting away with a stream of water aimed at the sensor locations in the tank. Of course one should also take the time to clean the rest of the tank also. Works every time.

You are correct, I miss posted by calling the problem tank the holding tank when it is indeed the gray water tank that is causing my problem, sorry about the confusion.

I find no drain plug in the tank, only the main dump valve and it's a ways from the tank. It would be difficult to thread anything up into the tank. I might consider installing a plug in the bottom of the tank myself.
LadyRVer
Explorer II
Jul 05, 2017
If I really want to do a super clean job and most times the sensor will read correctly when done, I drag a garden hose through the door and go down through the toilet with the slide valve held open by the hose. Do not get distracted or you might have an overflow... I then close off the valve on the outside and let it fill 2 or 3 times and pull outside valve again. Sometimes I put some laundry soap down the bowl while I am doing this. I have a back-flush clear elbow on the outside, but the pipe goes across to the other side of the trailer and doesn't do much good.
ernie1
Explorer
Jul 05, 2017
You didn't mention it but I assume you are having a problem with the gray water tank sensors and not the black. I take care of that problem by removing the drain plug and inserting my homemade wand which fits into the small drain plug hole and blasting away with a stream of water aimed at the sensor locations in the tank. Of course one should also take the time to clean the rest of the tank also. Works every time.
Hermes1
Explorer
Jul 05, 2017
I have found the black tank flush connection and flushing wands to be helpful but not a complete flushing of the black tank. In addition, thorough black tank cleaning often requires at least two cycles of filling the tank and dumping and not uncommon 3-4 times before no debris is seen exiting. Then if still having problems with tank sensor, try filling the tank 1/2 to 2/3 full adding some water softener solution and some laundry soap, then go for a nice drive, preferably on hills and winding roads to slosh the mixture around and agitate.

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