What tank additive should I be using?

If it was up to us, we’d prefer that you don’t use any tank additive at all! Why is that? All you really need is water, and plenty of it.

Sufficient water when using your holding tanks – especially the black one – will reduce and even eliminate odors, keep tank sensors working, allow your tanks to drain quickly and efficiently, and let your tanks accept waste to their full capacity.

“But we’ve been told to use some sort of additive!” We know; we get it. As RVers, we were told the same thing and for many years used pods, colorful additives, and just about anything we were given, told about, or bought at an RV store.

But those tank additives – enzymes, biological agenst, and chemicals – all intended to break down what’s in your holding tanks (especially the black one), dissolve your RV’s holding tank’s contents (feces, toilet paper, etc.) – as they claim they will – into a thick, sticky slurry.

That thick mixture is coating the insides of your tanks and fouling up those tank sensors (or the ability of the strip type to get accurate readings). It also causes odors, reduces tank capacity, and slows down what’s coming out (and even prevents the tanks from emptying completely!).

“So we just use water?” Yes, and plenty of it. Here’s some tips:

  • When you get to an RV park or resort, add three to five gallons (depending on your total holding tank capacity) to each tank as a sort of “priming of the system.”
  • When using the toilet, fill the bowl halfway. Whether it’s #1 or #2, flush the bowl, add another half bowl of fresh water, flush that down, and fill the bowl up halfway (for the next time).
  • Empty your tanks when they are 75% to 100% full. A full tank creates a swirling vortex when it is emptied, helping to keep your tanks clean.
  • When you’re traveling (and after you’ve emptied your tanks before you leave), add three to five gallons (depending on your total holding tank capacity) to each tank. This helps to lubricate your tank and can loosen any build-up inside.

So the big message here is to use plenty of water and to increase the water-to-waste ratio. The higher the ratio, the better your tanks will work.

But what if you really want to use a tank additive? In this case, we recommend our mixture of Calgon and Pine Sol. The Calgon is a surfactant and breaks the surface tension of the water, making all your tank and pipe surfaces slippery (waste will have a much less chance of building up). The Pine Sol is a great disinfectant and odor-fighter. It’s also a great way to knock down mold in your gray tanks (you add this mixture to both the black and gray tanks).

    Jim & Debbie Tome, Owners

    Hi, we're Jim and Debbie Tome and we're the owners of Kleen Tank LLC, the nationally-recognized and largest professional network of RV tank cleaning service provider.

    We've been RVers like you since 2004 and have traveled all over the U.S. in our Airstream travel trailer. We started the business about twelve years ago and have cleaned tens of thousands holding tanks in thousands of RVs. From tiny weekend travel trailers to monstrous fifth wheels to luxurious motorhomes, we've seen just about every situation there is with RV holding tanks and waste systems.

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