NoFlex VS Happy Campers: The Holding Tank Files Finale

ATTN: It’s kind of disgusting. Just saying.

I am finally getting back to our holding tank experiments, as promised. Alert readers with good memories will recall that we did a little product review on Zaal NoFlex Disgestor. We determined that it was very good at decomposing toilet paper, even in salt water, and we decided we’d be using this stuff all the time in our holding tank. In the comments section, one of our regular readers said that someone on his dock recommended a product called Happy Campers Organic Holding Tank Treatment. His neighbor claimed it worked just as well for less money. Hmmm. I like the idea of ‘less money’. Another reader said he appreciated our science experiment, but he was most interested in what the digestor did to ‘solid waste’. That is science code for ‘poop’.  It’s hard for me to resist these kinds of challenges. So between one thing and another, an additional experiment was born.

That's "Dr. Molecule", if you please.

That’s “Dr. Molecule”, if you please.

I purchased a container of the Happy Campers, got some supplies together, and tootled out to the Olympic Peninsula to the home of my sister, Amy. She is the mother of a 13 year old boy with an enquiring mind and a sense of humor. She also has a big dog. I needed both of those things in order to get this experiment off the ground.

My supplies:

1 container Happy Campers
1 container Zaal NoFlex Digestor
A bunch of brand new, unused plastic containers with lids
1 big container of sea water from the marina
Protective lab things like latex gloves, wigs, and lab coats.
A ready supply of dog poop.
Scientific measuring devices such as a food scale and our eyeballs.

The donor. Gonzo.

The donor. Gonzo.

The goal: To determine which holding tank additive works best to digest ‘solid waste’, i.e. poop. That’s right. We went there.

Method:  Since I was doing this experiment with my nephew and don’t want to be a bad science role model we tried to use the scientific method, sort of. We wanted to test the products with both salt water and fresh water. The fresh water is well water from Amy’s house, so there are no chemical additives. We set up 6 new plastic containers: two each for each product (one each for salt and fresh water), and two controls that would have only salt or fresh water but no product in them. We measured two cups of either salt or fresh water into each container and labeled them. Holes were punched into the lids to allow oxygen into the containers, just as our holding tanks are vented.


A bit too much.

We used 1.5 ounces of Gonzo poop for each container, weighing that out carefully. That was the most disgusting part of the experiment and offered plenty of opportunity for adolescent joking around. I’m talking about me and my sister, not my nephew. He’s way too mature and stoic to make dog poo jokes. We started this part of the experiment inside the house, but after opening the container of poo, thoughtfully collected by my sister before I arrived, we decided it was best to move it outside. I like doing experiments like this where other people have done the heavy lifting.

We initially decided we would add 1/4 teaspoon of each product to 2 cups of either salt or fresh water to see how the products responded. Deciding how to use the product was difficult because the directions are different for each one. Using the NoFlex requires that you add small amounts at a time to the tank. Using the Happy Campers requires that you add a scoop of the product to a gallon of water and flush that solution into the tank. It was a little bit like comparing apples and oranges but we needed to start somewhere, so the decision was made.fullsizeoutput_287


Adding the Happy Campers product to the containers resulted in little action right off the bat. The powder went in and dissolved and that’s pretty much it. After a few minutes some small bubbles began to form on the Gonzo poo.



Adding the NoFlex digestor to the water was vastly more entertaining. Immediately the Gonzo offering began to fizz and bubble in a most satisfying way. Interesting things were obviously beginning to happen. Within 20 minutes the largest piece of solid waste in the fresh water container was fizzing and floating near the top of the container. That’s probably more than you really want to know. Here’s the video. We get pretty excited and Amy uses a really long word.



The controls, both fresh and salt water with Gonzo poo added, sat there sullenly refusing to form bubbles or fizz or pretty much anything else. They were really boring.

Happy Campers, both fresh and salt water, within the first hour.

Happy Campers, both fresh and salt water, within the first hour.

At this point, I packed up my stuff and went home, leaving the experiment in the capable hands of my nephew and asking for a report back. They moved the containers inside to the table and then went to see a movie. When they got back, a few hours later, I got this text:

“Just got back from watching Miss Peregrine’s Home for Peculiar Children. The two with NoFlex are completely sludge on the bottom. Happy camper is mostly solid still. ”

Translation: Both the salt water and fresh water to which we had added the NoFlex had almost no remaining solids, only a layer of sludge on the bottom of the container. The Happy Camper’s had a thin layer of sludge but was mostly still solid waste.

About 7 hours of sitting and the NoFlex has taken care of most of the solids, even in salt water.

About 7 hours of sitting and the NoFlex has taken care of most of the solids, even in salt water.

At this point in the experiment, the No Flex was clearly ahead of the game for sheer entertainment value as well as fast acting digestion of solid waste. But had we given Happy Campers a fair shot? Was our experiment designed well considering how different these products are?


Skippy, the unsuspecting donor.

I decided it was not, that Happy Campers deserved another shot at the win. This time I mixed up a proper solution according to the directions on the package. I didn’t bother with the salt water solution, just fresh. Since I do not have well water, I let the water sit overnight to dissipate chlorine. And I used our dog Skippy as a donor. The same amount of solution and poo was used.

The results were marginally better. After 24 hours, the solid waste was breaking down, but it was going to take its time doing it. Compared to the 7 or so hours the NoFlex took, this was a dramatic difference.

After sitting in the solution for 24 hours, there is decomposition, but still a lot of solid waste.

After sitting in the solution for 24 hours, there is decomposition, but still a lot of solid waste.

Conclusions: Both products will break down the waste in your holding tank, but based on this experiment, the Zaal NoFlex is going to work faster. I do not know how long it would take the Happy Campers product to break down the waste because I didn’t want to keep dog poo solution on my kitchen counter for that long. It’s gross. Perhaps the difference is kind of like the story of the tortoise and the hare. Slow but steady will get you there.  And you do need to add a small amount of NoFlex on a regular basis. Perhaps that’s where the cost saving issue with the Happy Campers comes into play.

For our purposes we’re still putting our money on the NoFlex, although we’ll keep the container of Happy Campers in reserve in case we run out of the NoFlex.  If there is any build up in the tank, the NoFlex will handle it, something the Happy Campers is not designed to do. In fact, they sell a different product on the Happy Campers website, designed to clean out the holding tank. Their website also makes the point that their product ‘lasts longer’ than any other product of its kind on the market. Perhaps that’s what we were seeing in our results. Maybe this product doesn’t work as fast, but it works longer.

That’s an experiment for another day. After all, research always brings up more questions than it answers. But I’ll leave you to decide if you want to go that far. And you’ll probably have to find your own 13 year old boy to help.

Studying up on the ingredients of these products and falling down the rabbit hole of research. Got to love a kid with an enquiring mind.

Studying up on the ingredients of these products and falling down the rabbit hole of research. Got to love a kid with an enquiring mind.


32 thoughts on “NoFlex VS Happy Campers: The Holding Tank Files Finale

  1. We sound like complete dorks. Oxygenization? Is that even a word? I’m glad you followed up because using the Happy Campers without making the concentration into a solution first just felt wrong. Also, they are completely different products and I do believe ended to be used in different ways. And poop. HAHAHAHA

    • We ARE complete dorks? I mean who else would do this? Also, yeah, that’s why it took me so long to write this up. I knew the original experiment was wrong in terms of the HC and was trying to avoid doing a follow up experiment. Procrastination. Glad THAT’s over.

      • Thank you for letting me do the experiment with you. I enjoyed getting to play with the poo and you article thing made me laugh.

        • I win the ‘coolest aunt’ award for this. Also, come down to Mexico and I’ll let you add the NoFlex to the real deal. Also, whale sharks and friendly sea lions.

  2. Melissa, you need to put a warning label on this post: Do NOT read when others are sleeping! I had to work really hard not to laugh so loudly that I woke everybody else up this morning. Great read. Great experiment (Gonzo poo — hee hee hee). And really interesting results.

  3. Good report. We use Happy Camper in the holding tank in our little ToyHome, Flipper, and have been pleased with its odor-abatement properties. But, truth be known, there is still usually some build-up in the tank at dumping time. May have to give the No-Flex a shot. Never even heard of it before.

  4. We have been using Zaal in our vacuum system holding tank for three years. When we pump out, we rinse the system with fresh water until the discharge runs clear as seen through the clear section of the Shilshole pump out hose. On the rare occasions that we remove the level sensor to clean off the probes, we can see sides of the holding tank have minimal buildup,

  5. Fantastic, thanks for this! Faster is gooder as far as I’m concerned. I’ll be moving over to Zaal when my Happy Camper is all used up.

    Gonzo looks like a good old dog. Thanks also to him and to Skippy for “giving one for the team”.

    • I like ‘faster’, too. And I’m willing to add a wee bit every so often to keep the fire stoked.
      Gonzo is a good sport. But shhh, we never discussed this with Skippy.

  6. This post cracked me up! I think you’ll be getting a call that you’ve won this year’s Nobel prize for scientific discoveries. This is certainly the scientific breakthrough of the year, if not decade. You’re an awesome role model for your nephew and your dedication to the scientific method is inspiring 🙂

  7. What a great post! Nicely done.
    We have been using NoFlex since we got introduced to it by our pumpout guy, Dwight, with PumpMeOut (he has two pumpout boats, Number One and Number Two)

    s/v Eolian

  8. Wow, what an experiment! Thanks for dealing with such a “crappy” topic .. and thanks ti Skippy & Gonzo too!

    We’ve not addressed our holding tank yet .. so much to learn! I’ll definitely pass on the NoFlex info to my husband… it’s his job, right?!

  9. Wow, what an experiment! Thanks for tackling such a “crappy” topic .. and thanks to Gonzo & Skippy too!

    We haven’t addressed our holding tank yet, so glad to know what to tell my husband to use. It’s his job, right?!

  10. Quick question .. we’re familiar with “Camper Chem” and don’t like the smell of it. Does the Zaal have a similar smell .. or hopefully something better? Also, do you add to the toilet, and how much/often?

    Thanks again!

    • It has no smell. I’m familiar with those overly perfumed smells you get in public bathrooms and they won’t work on our boat. You add this stuff directly to the toilet. Just a little bit, like 1/2 tsp, at a time. How often you add depends on your own particular situation.

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  12. Excellent research! Science for the win!

    We have been using Happy Camper for years in our RV, and now that we are spending half each year on our boat we’ve had a recommendation to try Zaal.

    Our container just arrived – and now I am actually looking forward to trying it out. *grin*

    – Chris

    • You will not regret the purchase! We continue to be very pleased with this product. I understand that many folks swear by Happy Camper. I think they just do different things. Hope you’ll stick around the blog!

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