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My first Black Tank Simulator experiment turned out to be pretty popular.  If nothing else, it was unique, and I don’t think anyone had tried it before.  I got plenty of suggestions for ways to make the experiment better.  Many of these suggestions were good, and I incorporated them into this experiment.  One of them, it turns out, makes a huge difference in how things go.

 

In this video, I walk you through some of the changes I’ve made to the experiment setup, and then I proceed with four runs to test the following products:

 

First, I want to say that I am ONLY looking at the TANK FLUSHING PERFORMANCE in these tests.  I know that the Sewer Solution can do other things like pump uphill.  I know that the Tornado Rinser requires you to modify your RV to use it.  But for now, I’m just focused on one thing:  How well will each of these products flush out your RV black tank?

Having run the tests, I have to say, I was a bit surprised and enlightened by the results.  Even Stef got pretty interested in how things were turning out, because they weren’t quite what we expected.  I know the video is super long, but I didn’t feel I could cut much more out without taking away some valuable footage.

At any rate, when the tests were all done, and I had a chance to think about it for a while, I came up with the following conclusions:

Conclusion 1:

Your plumbing configuration makes a big difference.  Just two simple 45 degree elbows completely change the effectiveness of a “Drain End” flush system.  So the first thing I’m going to recommend is to stick your head under your RV and check out how your plumbing flows from your black tank to the gate valve and outlet.  Knowing this will help you pick out a tank flushing system that will work for you.

Conclusion 2:

The clear section you may have added to your drain setup is likely lying to you. This is still somewhat dependent on plumbing, but in all cases – the water was sparkly clean in the clear section before the tank was completely clean.  If you’re going to buy one of these clear gadgets so you can tell when your tanks are clean, don’t bother… they’re not.

Conclusion 3:

The “Drain End” flush systems without a way to shut off the flow out of the tank are completely worthless unless you have a straight shot back into the tank.  The water won’t make it back into the tank, and you’re just cleaning out the piping until the first bend.  They just waste water.  Don’t bother.

Conclusion 4:

Even when you can shut off the flow, the “Drain End” flush systems are no more effective than just filling the black tank (again, unless you’ve got a completely straight shot back into the tank).   Don’t waste your money.  You can fill the tank by flushing the toilet, or, depending on your RV, by using a bathroom faucet that drains to the black tank – and then you won’t have any additional pieces of sewage-contaminated equipment to worry about handling.  If you’ve ever looked at one of my RV review checklists – now you know why “does the bathroom sink drain to the black tank” is on there.  It’s easy, it’s convenient, and it works just as well as almost anything else out there.

Conclusion 5:

The only system that cleaned the walls with any real effectiveness was the Tornado Rotary Tank Rinser.  I’ll generalize and say those results are probably similar for any built-in rinsing system.  The in-tank rinsing system can also do anything a “drain end” system can do.  The downside here is that unless your RV came with one, you have to drill a hole in your black tank to install it.  I’m not sure I’m willing to go there yet.  But if your coach came with a rinse system… use it.

And Finally:

If something is heavy enough to sink to the bottom of the tank, you’re probably not going to get it out of there, except perhaps by luck.  Some of the “simulated waste” in each of the runs would settle on the bottom and just sit there.  Whether or not it made it out was simply “luck of the draw”.  One reader has already suggested that this highlights the importance of always leaving a bit of water in the black tank to keep the inevitable leftovers from “hardening”.  I couldn’t agree more.

So What’s Next?

That settling waste leads me to what I think will be my next experiment… tank treatments.  From watching this video, it’s pretty apparent that getting waste consistently liquefied, and fast, is key to getting it out of the tank.  So for my next experiment, I’m going to test some tank treatments to see which one does that the best.

That experiment will take a while to set up and carry out.  I’ll have to figure out a way to keep the tank indoors (to eliminate any temperature and lighting effects).  I’ll need to generate simulated waste that’s even more similar to the real thing, because now we’re getting into chemistry.  And I’ll need to run the experiment for days at a time to give the treatments time to work (and because that’s how we use our RVs).  I’ll be working on these challenges, and I will get it done eventually.

The test run sheet with my procedure is attached just below.  Hope you enjoy the video.  Cheers!

Clear Black Tank Test Log (2nd experiment)

Full Disclosure: I paid retail for all of the products used in this test, with the exception of the Sewer Solution. Valterra had provided that for an earlier test, but did not place any restrictions on how I could use it. The procedures, results, and conclusions you see are all my own.