“Bubbling” Toilet

[Moseh]

My 5th wheel has a Thetford toilet. Recently when the pedal is pushed to flush, is sort of “bubbles” (hard to describe). It otherwise flushes fine but curious as to what is causing this. Maybe gas/air coming up from the tank? Just want make sure this isn’t a symptom of a hidden problem.

[GHen]

Sounds like you have a classic poo pyramid plugging your vent. You need to fill it and dump it a few times. Maybe even fill about 3/4 and drive around the block and dump again.
Also, fill the toilet full of water then flush, as many times as needed until it clears.

Are you at a site where you leave the black tank open all the time?

[Moseh]

Originally Posted by GHen

Sounds like you have a classic poo pyramid plugging your vent. You need to fill it and dump it a few times. Maybe even fill about 3/4 and drive around the block and dump again.
Also, fill the toilet full of water then flush, as many times as needed until it clears.

Are you at a site where you leave the black tank open all the time?

Thanks for the info. That makes sense.

No, I very rarely leave the blank tank open.

[norty1]

On my rig, it means time to dump the black tank.

[Jagiven]

From the description it sounds like the classic poop pyramid. The pyramid forms from a lack of water in the tank.

Once you get the tank clean. After dumping make sure to add a LOT of water back into the tank and always flush with lots of water. After dumping, I try to add about 10% of the tank volume of clear water back into the tank. Only time my tank is dry is when I winterize.

To clean the tank, add water softener to the tank. Some people use Calgon Water Softener, I use liquid Fabric Softener (I keep a jug in the shop). I will mix up about a cup to 5 gallons of water. Usually I will mix up the solution in a 5 gallon bucket and pour it rapidly down the toilet after dumping. Drive home, and let is slosh. Drive to the next camp and let it slosh. I will repeat this a few times as needed. I use the same solution in the grey tank when the sensors start to act up.

The water soften changes the surface tension of the water and makes it "wetter" so it is easier for the water to soak into the pyramid.

Some people also swear by adding a large bag of ice cubes down the tank right as you are getting ready to take off, so it can slosh around and break up the pyramid. I have never tried this technique.

If you have a tank flush, it might be well worth staying at a full hookup site, and flush and flush and flush after a trip or two with the water softener. It is difficult to get rid of a poop pyramid especially in a 5ve. I would use water softener and a lot of water for a few trips to ensure the pyramid is gone.

Good Luck.

[norty1]

I have heard of the vent pipe extending into the tank to far and when the tank fills up higher than the vent it no longer functions and can bubble when flushed.

As long as the drain works, it may just be something to be aware of.

[TCNashville]

Originally Posted by Moseh

Thanks for the info. That makes sense.

No, I very rarely leave the blank tank open.

Never ever leave the black tank open. Open it only to dump.

[billcf7]

Originally Posted by Moseh

Thanks for the info. That makes sense.

No, I very rarely leave the blank tank open.

Very rarely? Never leave black open

[GHen]

To help understand, most tanks have a slight slope, the toilet near the high side, the drains near the low side. So the flush water goes to the drain valve area leaving the solids below the toilet, without lots of water, the solids get more solid, lol.

When we first got our rig, we had the same bubbling problem a few times, until everyone here helped educate me.

I agreed with above, after a good clean dumping of the tank add a couple gallons of water to keep everything soft. Sometimes we add toilet chemicals if it’s hot out, sometimes we add a cup of borax to help break everything down if it’s cooler and we don’t plan on dumping for a while. I need to try the fabric softener on our next trip.

We normally dump our gray tanks twice for every one black tank dump. Dumping with a nearly full tank seems to work better for us. We also generally don’t dump before leaving a park, we take it on the road and dump as soon as we arrive at the next location so it gets a good mixing up while on the road.