Bonnie and I had missed the memo, “Thou shalt not leave the black tank valve open while living in an RV park.”

All was good for months until one day the toilet would not flush.

Not Good

Search for “how to unclog an RV toilet.” led to quite a few explanations and remedies. Some were quite amusing and enlightening.

It turns out that leaving the black tank valve open causes all the liquid to run out, leaving the solid materials behind.  

Cameras like colonoscopy cameras for RVs revealed that a Great Pyramid of Poo could build up and block the toilet.

Remedies ran from running near-boiling water down the toilet to using tank cleaning chemicals not available in Canada.

I reasoned that hooking up a water hose to the ‘enema’ connector may erode the pyramid enough to get things to flow again.

So Bonnie was inside on the phone watching as I turned on the water.  

“Stop! Stop! She cried.” as the sludge overflowed into the grey tank and started coming up the sink.

We were in a stinky mess.  Couldn’t use water for anything.  Possibly may need to take the unit into a shop to get the tanks cleared and possibly replaced. The costs could be in the thousands of dollars.

At least there were toilets and showers at the RV Park.

The Great Wall

It was evident that what we had was more like a Great Wall at the tank outlet than a Great Pyramid.

Various remedies came to mind.  One was to move the RV next to the sewage dump at the RV park and poke something in from the outside.  

I had visions of creating a YouTube-worthy Fountain of Poo in front of the office and lounge, like Robin Williams in the movie RV (no, they did not get their deposit back on the rented RV).

A friend offered to loan us some plumbing snakes and we went to Canadian Tire to see if they had something that would at least direct the geyser downward towards the drain.

They had the perfect attachment, the Rhino Blaster.

The device is intended to go between the tank outlet and the sewer hose, with a connector to attach a hose and flush water into the tank from the outside.

It turns out that the snake with a 1/4 “ flat metal ribbon and a scraper at one end would fit perfectly through the water valve.  

There is a rubber seal to help avoid backwash that I kept open with a straw to allow me the feed the snake ribbon back through the valve.


1/4 inch ribbon snake from Cobra

I then connected the Rhino Blaster to the tank outlet and the sewer hose to the other end.

In the very least there would not be a fountain of poo and we could try the operation where we were sitting and not in front of the office and lounge.

You do not want to be witnessing a fountain of poo while sitting in the hot tub!

It took about 5 minutes of working the snake to get a tiny flow of fluid to come out.

There is Hope After All!

Bonnie was dumping boiling water down the toilet to help loosen up the sludge. Many of the online remedies recommended this.

It took close to an hour of working the snake to get enough of the sludge out to risk running more water down the toilet and sinks.

We then carefully filled up the tanks and flushed out repeatedly until we got good flow and nearly clear fluids.

We will repeat every day for a while, then go to the usual practice of draining and flushing the tanks every 5 days or so.

It is safe enough to leave the grey tank open all of the time, though an occasional flush would be good.

Tank Maintenance

A few of the videos we watched described an alternative to dropping treatment pouches (bog candies) down the hole using variations of the Geo Method.  One used Borax and Dawn dish soap with a chemical explanation why the Borax was able to break down sludge and oxegenate the layer where anaerobic bacteria generate the stinky gases.

Makes sense to me.  

Here is a good video that adds the use of water softener to the Geo Method.

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