Grey tank sensors & flushing

[swingby1]

2011-3665RL
I purchased my rig second hand from a VERY meticulous couple. The black tanks had never been used. I’d assume they same for the (2) grey tanks, however, both sensors are showing 3/4 full when they are full. Is there a way to clean them? If I wanted to replace them (sensors) how would a go about it?
Related issue- in an attempt to clean the sensor On the rear (shower), I attempted to fill the tank with a hose via the shower base. The shower must be draining into the black tank as it over filled the black tank (luckily, I had just finished a thorough cleaning of the black tank)
Is this normal? I though the grey tank was for the bath sink and shower drain?
Dan & Linda
Hurricane, Utah

[DutchmenSport]

Tanks sensors almost always never work correct. The best thing you can do to help the sensors work correct is to dump your tanks. Then add about 10 gallons of water and go for a drive. The sloshing of the water in the tank will pulverize the sensors, removing "stuff" caught on them and cleaning them.

If this is done every time the camper is moved, the sensors will work more reliable. When the camper sits stationary, sensors will get crud caught on them.

Also, you do not need to dump a bunch of RV tank chemicals down the tanks. Anything you use for laundry and anything you use for washing dishes in the tanks will help keep them clean and also help clean the sensors. More REALLY is not needed. As always, when flushing your tanks, use lots of water.

So, when you travel from home to your camp site, add about 10 gallons of water and add about a 1/4 cup of Dawn Dishwashing liquid, or a half cup of Tide Laundry Soap, or Automatic Dishwashing liquid, or laundry washing machine softener, or all of these and go to the first destination. When you move again, do it again. Do it every time you travel, dump at the next location and start over. This is what it takes.

[rohrmann]

I never look at the sensor levels for the waste tanks, totally unreliable. The fresh tank is the only one that seems somewhat accurate. I wouldn't waste my time worrying about the sensors.

[RMcNeal]

I've used a product called Unique tank treatment for a few years now. It works very well. I've also used Happy Camper, but IMO the Unique works better.
They make a sensor cleaner which I used once on my black tank. It fixed the sensors for a while, but alas, they got dirty and started to read incorrectly again. I would imagine it would work fine for the gray tanks as well.
https://www.amazon.com/Unique-RV-Sen...xpY2s9dHJ1ZQ==

[jimcol]

Originally Posted by rohrmann

I never look at the sensor levels for the waste tanks, totally unreliable. The fresh tank is the only one that seems somewhat accurate. I wouldn't waste my time worrying about the sensors.

Following what Bob has said this is a tried and true method. When the toilet starts burping when flushing, dump the black tank. When showing and water starts backing up in the shower base, dump the gray tank. When water won't drain from the kitchen sink, dump the galley tank. Over time you will get use to your usage and you'll just know when it is time.

[swingby1]

Thank you all for your replies. There was a second part to my question concerning if the shower is supposed to drain into the grey tank or black tank. I tried filling the rear grey tank via the shower. After running my hose for several minutes, I heard the toilet hissing. I stepped on the toilet flush to stop the hissing BUT I got an explosion of water blasted at me (luckily I had just finished a thorough cleaning of my black tank). Shouldn’t the shower be draining into the grey tank? Both of the drain levers were closed. I’m baffled as to why the black tank filled vis the shower drain

[jimcol]

Never known or heard of a shower draining into the black tank. Have heard of the washer drain going to the black tank but never the shower. You may have to drop the bottom covering to expose the plumbing.

[rohrmann]

Originally Posted by swingby1

Thank you all for your replies. There was a second part to my question concerning if the shower is supposed to drain into the grey tank or black tank. I tried filling the rear grey tank via the shower. After running my hose for several minutes, I heard the toilet hissing. I stepped on the toilet flush to stop the hissing BUT I got an explosion of water blasted at me (luckily I had just finished a thorough cleaning of my black tank). Shouldn’t the shower be draining into the grey tank? Both of the drain levers were closed. I’m baffled as to why the black tank filled vis the shower drain

None of your tanks should become pressurized regardless of the source of water filling them. I'm guessing you are not the original owner of this rig, and if so, it sounds like someone has done some strange plumbing modifications. Dropping the coroplast like was suggested should be done soon so you can see what has been done to the drain system that is not right.

[twindman]

My bathroom sink drained into the black tank. I could see the pipe in the back of the passthru wall. So they don't always connect the pipes properly.
Also, with the pressure thing, could it be something about the vent from the roof being plugged. I seem to remember someone had a problem like this.