Black tank smell

[Retired mountain folk]

Originally Posted by Jay2504

We are camping and have a problem with the black tank. When the toilet is flushed we get a bad smell coming up from the toilet while the foot valve is pushed. I have checked the vent pipe and it seems tight. I climbed the ladder and you can’t really see anything, but I had her flush the toilet while I was up there and you can hear sound of the water running into the tank through the vent. I even closed the bathroom door and ran my Vortex II fan in full reverse and still got smell. The weird thing thing is that it’s not 100% of the time. The tank is about 1/2 full, we are using the blue stuff like always, I even added more. I always use the black tank flush. This didn’t start until the 3rd day. Any idea what is going on? Thanks in advance. Jay

We use the brand “pure power blue” used to use that other brand” but this brand seems to stop the smell. When your opening the flapper in the toilet by pushing on the pedal, the smell in the holding tank is coming back up at you. We don’t use the rinse, if you have a power spray on your connection to your tank rinse, ( if not you can put a power rinse connector on the tank, we did on our older one). That all you need, it sprays down the inside of your tank, we do that, empty, rinse down again until we see it’s perfectly clear coming out (get a clear elbow or degree attachment so you can see it). then just put the recommended amount, plus one quarter of that amount for good measure and that should take care of your problem. If your tank isn’t extremely clean, it may take a couple of dumps to make the smell go away after using the good brand. And after cleaning out with water spray. Think of it as a porta potty, the smell comes out of the hole…..

[Retired mountain folk]

Originally Posted by Jagiven

When we have our bathroom ceiling vent on we tend to get odors pulled into the TT.

Dawn is fine. Personally I like liquid fabric softener better. Maybe 1/2 cup with 3 gallons of clear water after dumping. Let is slosh on the way home and to the next camp. Most of the time, 1 treatment and my tanks are happy again for the season. I also will put it in the grey water tank as needed to help clear the sensors.



We tend not to use our shower as my son and I are to tall, and there is not enough room. So we all tend to use the bathhouse. Sometimes as we drive the water sloshes out of the P-Trap and we get an odor, so I keep a drain plug in.

Shower and sinks go to the grey water tank, not the sewer black tank, so if your smell is coming out of your shower, you’ve got a problem. There is a deodorizer made for the grey tank, use as directed, it’s like moldy water in that line, shouldn’t be sewer unless your putting garbage into the kitchen sink? FYI. GOOD LUCK

[Hollander Mutthaulers]

For 26 gallon tank have used 2/3 cup Calgon, 1/3 cup Dawn followed by Happy Camper with three gallons of water. Dump almost all kitchen sink water down toilet to keep as much liquid as possible in black tank. In five years never much odor but at times can get odor blown in from fantastic fan which, on our little roof, is very near black tank vent stack.

[hikerjohn7]

Originally Posted by RedHorse1

If you had the doors/windows open there may have been enough pressure difference to pull fumes from the black tank during the flush. Running the bath fan in reverse may not have overcome that. Any other roof vents open (kitchen)?

We had several class As and seldom have we smelled gasses from the toilets when the vent fans were not running. I advise my grand kids to use the vent fan when they use the toilet but to make they flush quickly so the vacuum does not have time to pull gases from from the tank. Another thing I do is to keep the black tank dump valve closed until I dump the tanks. This isolates the tank from the septic tank system. And I don't go more than about three days between dumps.

So... I am thinking you probably have some condition that is causing the air pressure in the tank to be higher than that in the bathroom and I wonder if, on hot days, the septic tank systems from the parks could be doing it. If so, keeping the black tank dump valve closed might help.

As for cleaning the black tank, I would think that would have only a marginal effect since the tanks smell about as strong empty as they do partially full.

[Jay2504]

I’m not sure what the problem actually was. I did twice the usual amount of flushing of the black tank when we dumped. There was nothing unusual about what came out. We are now at my nieces house, in another state camping in her driveway with no odor problem at all inside or outside. It is warmer here and we have been using the AC, that is the only real change. I have been looking for Happy Camper, but can’t find any. I will order some when we get home. Again I want to thank everyone for their ideas and input. Jay

[Bayoutalker]

Originally Posted by 2021JayFlight28BHS

I use this (1/4 cup of blue dawn and 1/2 cup of borax) in my tank between outings and after a black tank flush, it seems to help with odor and breakdown of residual….also it’s good to leave a couple of gallons of water in the tank between trips. I also put ice in my black tank right before I leave for the campground…figure this will help “scrub” the tank on the drive there.

I use Borax, Blue Dawn and Calgon Water Softener. I use the cap for the Calgon as a measure and put one of each in the tank. Since I started this I have had no odor problems and my tank flushes easily. When I dump I flush well and add the mix after using it to clean the bowl. Just flush and you are ready for the next trip. We live in ours and dump once a week.

[Marmot]

Originally Posted by Jay2504

We are camping and have a problem with the black tank. When the toilet is flushed we get a bad smell coming up from the toilet while the foot valve is pushed. I have checked the vent pipe and it seems tight. I climbed the ladder and you can’t really see anything, but I had her flush the toilet while I was up there and you can hear sound of the water running into the tank through the vent. I even closed the bathroom door and ran my Vortex II fan in full reverse and still got smell. The weird thing thing is that it’s not 100% of the time. The tank is about 1/2 full, we are using the blue stuff like always, I even added more. I always use the black tank flush. This didn’t start until the 3rd day. Any idea what is going on? Thanks in advance. Jay

After each black tank dump, rinse the tank thoroughly and close the valve. Now, pour an ounce of Dawn or LA Awesome in the tank and fill with water. Let it sit for an hour. Drain and rinse the tank again. Close the valve. Add a scoop of Happy Camper and a gallon or two of water.

[Cujonaut]

Originally Posted by Marcm157

And on a side note - I use Happy Camper tank treatment. I don't often speak for a specific product but to me this stuff is great.

X2 on the Happy Campers. Stuff works great.

HAPPY CAMPERS Organic RV Holding Tank Treatment - 64 Treatments https://www.amazon.com/dp/B007S0LDME...7DF9F48XCHZF7E

[saunterr44]

Its all in the technique - close the lid, partially press the pedal so that you have lots of water, then press the pedal QUICKLY, fully to the floor, and then BACK UP quickly.

You want to minimize the time that poop chute is open, of course...

[Marine71-76]

Originally Posted by Marmot

[snip] and a gallon or two of water.[snip]

We had our previous unit at the manufacturer for repairs & tank replacement and we discussed the black tank. He said 10% water is the minimum amount of water that is placed in the black tank. So for a 75 gallon, we put in 8. We did question his reasoning - for those not living in their unit full-time - water will slowly evaporate and it allows the water to slosh around while driving down the road.

Purchased this https://www.amazon.com/Orbit-56854-H.../dp/B07J2V2QWW and now using it to measure the water versus DW pouring gallons of water down the toilet.

[thenne1713]

Originally Posted by Jay2504

We are camping and have a problem with the black tank. When the toilet is flushed we get a bad smell coming up from the toilet while the foot valve is pushed. I have checked the vent pipe and it seems tight. I climbed the ladder and you can’t really see anything, but I had her flush the toilet while I was up there and you can hear sound of the water running into the tank through the vent. I even closed the bathroom door and ran my Vortex II fan in full reverse and still got smell. The weird thing thing is that it’s not 100% of the time. The tank is about 1/2 full, we are using the blue stuff like always, I even added more. I always use the black tank flush. This didn’t start until the 3rd day. Any idea what is going on? Thanks in advance. Jay

YEAH, NOT A GOOD IDEA TO RUN FAN DURING the FLUSH... and yeah, that stuff does smell... bad. You can run fan AFTER flush, with valve closed, bringing FRESH into room and out the roof... but NOT when VALVE OPEN. (kinda self-inflicted pain?) and DO put water in SHOWER DRAIN/TRAP, EVEN IF YOU DO NOT use the shower... DRY= it does NOT TRAP the bad gases..

[Poppyof5]

I know when its hot out I will leave a U in the drain hose, acts like the P trap in your house. Also we use happy camper and drop a couple deodorant pods. Remember water is your friend so be sure and use plenty when you flush (we have our grandchildren count to 10 when they are with us

[Slyflye]

I watched the same video and use his method and haven’t had any issues.

[gunafulltime]

Originally Posted by JFlightRisk

Although the black tank flush is a nice feature, my BIL used it exclusively on his new SOB TT for 2 seasons, and had the same problem. Right after he flushed it to his satisfaction, the smell was still there. I connected our clear fitting to his outlet, went inside with our flushing wand and gave it a rinsing while he watched what was coming out. Two things happened. He was in shock at what was still inside the tank, and then the smell went away for the rest of the trip.

We don't have a tank flush fitting on ours, so it gets a "wanding" after every outing, and never an issue with odor.

Which wand do you use. I have one, but I don't think it's long enough.

[Johnynorthland]

Others here have given great advice that you should try. Also Make sure you keep your grey tank valve closed at all times. I was getting orders up from the parks sewer systems through the grey tank and thought it was my black tank! We part time 6 months a year. We also use happy camper and it works. (Switched from the blue after 5 years)

[videoarizona]

Happy Camper for past two years.
The Geo Method, periodically, for general cleaning.
The wand and tank flush as well once in a while.
No issues. No smell.

[JFlightRisk]

Originally Posted by gunafulltime

Which wand do you use. I have one, but I don't think it's long enough.

Sorry for the late reply, we were out of town for a few days.

We've had a Camco 40103 wand for many years. I did drill three more small holes in the end cap so it sprays in all four directions at once. I don't have to twist it all the way around any more to get the spray to all the sides of the tank.

https://www.campingworld.com/holding...788a9de963147d

They do make one with a swivel sprayer on the end, but I haven't had the privilege of using one of those, it may work better.

[lroyson]

I have a 2017 24RBS and had a the same problem with smells from the black tank when flushing. I replaced my stock vent caps with some new ones that were more open and have never had the issue since. I had read somewhere that the stock vent caps were too restrictive for the air to escape the vent properly.

These are the ones I replaced with:
https://www.amazon.com/Lippert-Compo...a-569424062280

[Weatherman1]

Especially the exhaust fan if the door is closed the air has to come from some where.
Down the air vent and out the toilet opening!

[57gasser]

Originally Posted by Jay2504

I’m sure it’s the toilet. Not hot at all outside, like 72 degrees. We had the door open and the vent fan on, which is kinda unusual for us. I thought that the vent fan was pulling smell out of the toilet, but it happened with the fan blowing air in to the bathroom. Should I add a little Dawn? Our unit is a 2020 24RBS. Jay

Jay, we too have a 24RBS, but ours is a 2019. Last year about mid summer we pretty much had the same problem. Also, the black tank sensor was giving inaccurate readings. I always used the tank flush after dumping, always let it fill up before dumping & thought I did everything right. Then came that awful stench that coulda gagged a magot off of a gut wagon. The fix, right off JOF, was before the next trip I filled a 6 gallon water tote & dumped it in the black tank along with one treatment packet. That sat overnight, & before leaving the next morning for a 200 mile drive to our destination in went 2/3cup of blue dawn. Left that mixture in there till the tank was filled before we left for home. Dumped & flushed, and...Problem solved!! Not one hint of stink since.also cleared up the sensor problem too.