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Clearing Stubborn Black Tank Odors & Sensor Cleaning

Clearing Stubborn Black Tank Odors & Sensor Cleaning

If the condition of your black tank is causing an odor in your RV, or if your tank sensors work poorly, your black tank likely needs cleaning. But, what’s the best RV black tank cleaner, and what kind of tank treatments keep the problems at bay? We’ve got answers in today’s post.

What Causes Black Tank Odors and Poorly Functioning Tank Sensors?

While dumping tanks on an RV isn’t the worst task in the world (especially once you’ve gotten used to it… and do it right), most RV owners would probably agree that dealing with the RV black water tank isn’t the main reason they started RVing. That’s especially true if solid waste and toilet paper have dried onto the bottom or sides of the tank because it hasn’t been rinsed thoroughly enough to leave it clean every time you dump.

Another issue crops up when an insufficient amount of water is used when flushing the toilet, which can cause the ratio of “solids” to “liquids” to be too high. This is most likely to happen when campers are boondocking and conserving fresh water.

Without enough water (and tank treatment) to break down solids, your black tank can leave your RV with a foul smell, and cause RV holding tank sensors to give false readings or fail to read at all.

Probe sensors are a common type of holding tank sensor. If they get gunked up with solid waste or toilet paper, the conductivity of the probe can be interrupted, leading to inaccurate readings on your monitor display. This is a common problem.

So, the tank sensor probes require a relatively clean environment to work properly. There are several ways to clean your RV tank sensors, but the best thing to do is to keep them from ever getting overly gunked up in the first place.

Nothing ruins a camping trip faster than awful black tank odor or tank sensors that don’t make sense. Luckily, both problems can be solved at the same time.

What Are the Best RV Black Tank Cleaners?

Fortunately, several products on the market can not only help to get your holding tanks clean but to keep them as clean as possible so you don’t keep running into the same problems.

Happy Campers Extreme

Happy Campers Extreme is designed to super clean RV holding tanks, restore poorly working sensors, and eliminate odors. Combined with a tank nearly full of fresh water, Happy Campers Extreme needs to sit for 24-48 hours to work its magic. A drive of about 30 to 60 minutes with that solution in the tank will help agitate it like a washing machine, allowing Happy Campers Extreme to soften and dissolve tank sludge.

We’ve used regular Happy Campers tank treatment and have liked it. It has no smell, is easy to dump, and has kept our tank sensors working well. For this reason, we’ve often recommended Happy Campers Extreme as a means of super-cleaning a smelly tank.

Note that this product can’t be shipped to California.

Happy Campers Extreme RV Holding Tank Cleaner
  • Super cleans RV holding tanks
  • Sensors: Restore poor working sensors
Happy Campers RV Toilet Treatment - 64 Black or Gray Holding Tank Deodorizer Treatments for RVs
  • ODOR FREE: Eliminates odors in the RV holding tank. Absolutely no chemical or sewer smell.
  • Septic tank friendly

Unique Clean-It Black Tank Deep Cleaner

This is another popular RV black tank cleaner powered by enzymes and probiotics that won’t damage seals or valves. It works in 48-72 hours, and according to the manufacturer, no driving is required.

Unique Clean-It breaks down solid waste and sludge in an RV black tank and digests all brands of household and RV toilet paper. It’s also safe for both home and campground septic systems.

Unique Clean-It RV Black Tank Cleaner Liquid, Enzyme Deep Cleaner Digests Waste Accumulation and Buildup, Eliminates Odor, Formerly Tank Cleaner (32 oz.)
  • New and improved formula! Using Clean-It is like power-washing your black tank. Works in 48-72 hours, no driving required. Cleans more effectively...
  • We took Unique Tank Cleaner, the strongest RV black tank cleaner on the market, and made it even stronger! Clean-It is powered by billions of enzymes...

PRO TIP: Speaking of the need for special “RV Toilet Paper”… can we finally put an end to this scam for once and for all?! If you haven’t already read our post debunking the myth, check it out now: Don’t Waste Your Money On RV Toilet Paper

Thetford Tank Blaster

Thetford’s Tank Blaster RV black tank cleaner works overnight. According to the directions, you can simply dump the tank the next morning and go.

Tank Blaster uses a “Micro-Foam Action” to improve surface contact with vertical tank walls and an active enzymatic blend to remove sludge and break down toilet paper and waste. Additives also work on hard water deposits on tank sensors.

Thetford Tank Blaster - Level Sensor Cleaner - Black & Grey Waste Water Holding Tanks & Portable Tanks Cleaner - 4 x 1.6 oz Packets Thetford - 96527,White
  • The first 2-in-1 tank cleaner specifically formulated for black/gray water and portable tanks
  • Cleans overnight - then just dump and go

What If Odor Remains or Tank Sensors Still Don’t Work?

If trying one of the above RV black tank cleaners doesn’t restore your sensors to good working order and/or remove a persistent smell, you may have a problem with struvite buildup. This is often the case with RVs that have been in use for several years.

Over time, even the cleanest holding tanks can collect a buildup of struvite, a type of crystal that forms from magnesium, ammonium, and phosphate and builds up on the walls of the tanks and inside sewer pipes.

Even our own waste holding tanks, which we kept as meticulously clean as possible, developed a struvite buildup over time. For more information and to see how we dealt with the issue, watch the video of our rig getting a “colonoscopy” of sorts!

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Sunday 5th of May 2024

I have a pail of Happy Camper and have tried 4 times to use it. It doesn’t dissolve completely no matter what I have tried. The smell from the tank was worse than anyother treatments I have used! If you want to try it buy the smallest container first to see if it works for you. I don’t even know were I can disppose of what I have left. Very disappointed for the price I paid!


Wednesday 8th of May 2024

@Kevin, according to the MSDS data sheet Happy Camper is primarily zinc sulfate, which is toxic to aquatic life in concentrated form so best to dispose of carefully. Appreciate your concern.

Many community landfills and recycling centers have days that accept household hazardous materials


Sunday 5th of May 2024

Have a 25 year-old Class C purchased used in late 2016. Took about a year of various treatments to get rid of TP and other build up on the walls and now it stays clean with exception of struvite crystals. I figured that has to be what’s remaining on the walls as the sensors rarely work properly.

I have a set of translucent wiz jugs that quickly formed a buildup of such crystals. Have tried many homemade and commercial remedies and nothing would touch the crystals. Finally found something that stripped them clean, which was adding Rid-X and clean water to the jugs, letting them sit in warm weather for a few weeks.

As my coach is in outdoor storage in Florida I’m trying that now with my dumped and rinsed black tank. It’s nearby so making several trips with filled water carboys and fresh Rid-X to add to the tanks and letting it work its magic. Will make a trip to a local campground to dump the tank in a couple of months. If the sensors are then consistently accurate, then I’ll know I broke the code

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