Black Water gauge always says full

Yes the black tank sensors are notoriously inaccurate. I can feel your frustration and can even imagine doing the no hose valve pulling myself. :) But before I did that I would open the toilet flush valve and take a look down into the tank as that is a much safer option in my book. :BThese tanks are typically not deep but rather long and wide but fairly shallow. So the tank bottom you see under the toilet is only about 1/2 inch shallower than the center of the tank.

Before I started dumping too many things into the toilet I would probably just fill the tank up with water from a hose and let it sit for a week and then drain it. But I am able to drain my tanks at home and this might not work for you if you cant.

But if you can drain at home try this.

• Fill the tank full.
• let it sit for a week.
• hook up the drain hose and pull the valve for about 5 seconds then close it again to lower the level in the tank some so it can slosh around.
• Then go take the trailer for a drive around the block or to the campground.
• Drain the tank fully and check the sensor.

Get a clear sewer connector like one of these and you'll be able to see if anything is coming out or not. Won't have to take that chance again.

In all of my rv's , I've always had a fairly decent working gray tank sensor and have used it to determine when the black tank should be flushed as we always fill it before the black.

The Geo Method works pretty good, but it still won't keep the sensors operating normally. After emptying the black, refill it with a black tank flush kit like this and it will help, but again will not guarantee the sensors to work normally.

Above all, when using the toilet, be sure to use plenty of water and never, never, leave the black tank dump valve open when camping.

Hope this helps

Ron

You can buy a cleaning wand that connects to a garden hose. Connect a sewer hose, open the toilet valve, stick the wand down the toilet throat, and let 'er rip.
Before I knew you could but one I made my own wand from a piece of capped-off 1/2" copper pipe and a hose connector. I cross-drilled and slotted the cap at 90-degree with 1/4" holes. I think it works better than the tank rinser on the TT.

The things aren't worth the contents of the black tank! :B

I feel wasteful but I always add water to the tank if it isn't full before dumping. I don't fill it but I don't like to dump if it isn't around half full at least. Thankfully ours has a built in flusher for the tank. You might benefit from a wand to get the sides of the tank hosed off. At least once. Once you have clean sides and sensors it should be easier to keep them that way.

there the worst thing on a rv don,t know I,d trust any of them ,we put calgon in our tank after every dump. still don,t trust it. we all so put extra water in the tank just before dumping ,helps move things out of the tank better.

What he said. gray sensor is semi-useful, black one is virtually useless.

Crud covering the sensor. They are notorious for being inaccurate. Search the internet for geo method of cleaning tanks. Usually involves adding bags of crushed ice water softener like 20 mule team borax and water and driving around for a while.