Black Tank Full... wait.. What??

If it's anything like mine,we have a buildup at the bottom where everything drops. If there is not enough water to flush it, it all drops and does not slide to the other end of the tank. This makes it look like a full tank although the sensors say different. I usually move it down with a flushing wand.

Tell the 5 year you or the DW will supervise the use other facilities and show her why. She is young enough to be educated.

I have a dump station at home so I'm going to dump 5 gallons at a time down and see if there isn't another issue

The burping isn't that bad it's the breath that will get you.

ronfisherman wrote:
Does your vanity sink drain into black tank like ours. I know how 5 year old's like to play washing their hands.

X2

This is more then likely the problem with the full tank. Buy a clear fitting and the next time you're at a FHU turn on the bathroom sink with the black tank open. Then note if the sink water is coming out.

unless you are boon docking turn the pump off. stops the waste quick.

I'll guarantee that these are very typical symptoms of a toilet paper teepee. Many people have a tendency to use as little water as possible when flushing an RV toilet. The end result is that waste and paper start to pile up right under the toilet discharge pipe. Here's how to solve it:

1. If you are already experiencing the signs of this problem, You'll need a flexible wand (see link below for one I use) to push down through the toilet in order to dislodge the blockage. With the water off, activate the toilet flushing lever or foot switch. Run the rod down the opening and move it around and up and down. It's a messy job, but after a little bit of manipulation, you'll hear a whoosh and the blockage will be gone. Then, turn on the pump, fill the bowl all the way to the top and flush the toilet. Repeat this twice to wash away any remaining residue. Note: I'd recommend wearing rubber gloves while doing this because the tube will get very nasty.

2. Prevention: We make sure anyone using the toilet knows the rules. If it's just liquid (no paper) you don't need to add any water to the bowl before flushing. If they use any paper at all, then they need to fill the bown at least 1/2 full of water before flushing, and hold the flush lever for about 3-5 seconds to allow enough water to move the paper and waste all the way into the holding tank.

Flexible Toilet Wand

We have a spray bottle that sits in the sink.. When something sticks to the side.. only a few squirts well aimed, and that is part of the fun, will dislodge it and put it to the bottom when a couple of seconds of rinse water will be down the pipe.

Trying to rinse the same could take a lot of fresh water down the same pipe.

While a 35 isn't considered a large tank, if you are conservitive, three people should be able to go 4 days

I'm guessing that your black tank didn't start the trip empty. I'm sure you know the dreaded pyramid black tank thing, thats also a possibility.
A small child over flushing of course could be the problem too but you can only find out if thats a possibility by careful observation on the next trip.