Black tank smell

Jay2504 · 08-02-2021, 08:07 PM

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

Grumpy · 08-02-2021, 08:13 PM

Air or fan on? If it's hot you will get a lot more odor.

Marine71-76 · 08-02-2021, 08:18 PM

We will occasionally get the same thing. I will empty the black tank, rinse several times then DW adds more treatment as well as a good squirt of blue Dawn. And as soon as she finishes with the blue stuff, she is switching to Happy Camper. We have been told it does a better job.

How old is your unit? How hot is it outside?

And are you sure it is the toilet? Why do I ask? Because I got up in the middle of the night & used the toilet. Boy did it stink!!! I asked DW about it in the morning. A little later in the morning, opened the front compartment door of the unit & boy was I hit with sulfur smell. Yep, one of our batteries had bit the dust.

Jay2504 · 08-02-2021, 08:23 PM

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

Marine71-76 · 08-02-2021, 08:28 PM

Quote:

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

If possible, would recommend emptying & thoroughly rinsing the tank then adding new chemical & a squirt of blue Dawn. See if that fixes the issue.

RedHorse1 · 08-02-2021, 08:49 PM

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)?

GHen · 08-02-2021, 10:13 PM

Couple of thoughts, if the fan was on and blowing air in, it could be pulling air from the vent and back in.

Also, if we are parked for a few days, a toilet paper pyramid can develop especially when the black tank is always allowed to drain into the sewer hook up. Once the pyramid starts to dry, it can block the vent and the tank vents through the toilet like a burp.

Keep the black tank closed and only dump when when nearly full. Use lots of water, add the Dawn, even ice cubes , drive around the park and shake it up before dumping black tank. We seldom dump the black tank at the parking site but will wait for a rest stop with a dump so it all gets mixed up a bunch.

**JFlightRisk** · 08-03-2021, 12:08 AM

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.

Jay2504 · 08-03-2021, 03:51 AM

Thanks everyone for the help. I am going to buy a wand to see if it helps. I do think that the windows open has something to do with the problem. I will also add Dawn to the tank. Jay

Marcm157 · 08-03-2021, 04:26 AM

Quote:

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

How close is your fan to the black tank vent on the roof? My stock fan wasn't so bad but when I switched to the more powerful Maxxair fan, if it was on and pulling air in we would get a bad smell when someone flushed the toilet.

2021JayFlight28BHS · 08-03-2021, 04:30 AM

Quote:

Originally Posted by Jay2504

Thanks everyone for the help. I am going to buy a wand to see if it helps. I do think that the windows open has something to do with the problem. I will also add Dawn to the tank. Jay

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.

Marcm157 · 08-03-2021, 05:39 AM

Quote:

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.

I use both a self installed black tank flush (I positioned it where I wanted the spray directed) AND the wand. I refuse to deviate from my Black Tank Routine! It has worked for us for years. My sensors are still working as they did when new and I have had virtually no tank issues.

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.

deepsea5 · 08-03-2021, 05:53 AM

Just a couple more things to consider:

1) Make sure your toilet bowl has an inch or so of water above the flush valve. This will ensure a better seal between the flush valve and black tank.
2) Do you use the bathroom sink and/or shower often? If not, and they have the standard P Trap design, the water in the traps can evaporate and let whatever foul odors lurking in the gray water tank vent into the camper.

TWP723 · 08-03-2021, 06:54 AM

You're gonna have odor, regardless. You're opening a tank "vent", for the lack of a better word, and letting all the accumulated gases in that tank out as water flushes in. You can curb the smell by doing what the others have said with the wand. It doesn't matter how well you think you're cleaning and flushing your tank, it'll always have a certain tinge to it.

joe66mal · 08-03-2021, 04:30 PM

Sometimes if you don’t have water ran through your sinks the p-traps can get dry and let sewer gas in from your grey water tank. The water in the trap seals gasses from coming up.

Jay2504 · 08-03-2021, 04:49 PM

An update, put in some Dawn, but we don’t move for a couple of days. I found out that the vent is working for sure, because I walked outside to the rear of the camper right after the toilet was flushed. I got hit with the smell from the vent. More and more I think it’s something to do with where we are. I will do an extra good flush job at the dump station. Jay

Jagiven · 08-03-2021, 05:40 PM

Quote:

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

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.

Quote:

Originally Posted by joe66mal

Sometimes if you don’t have water ran through your sinks the p-traps can get dry and let sewer gas in from your grey water tank. The water in the trap seals gasses from coming up.

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.

2021JayFlight28BHS · 08-03-2021, 06:06 PM

Check your surroundings, stayed at a KOA that was next door to a sewer pond… when they used the aerators in the pond, wow what a smell…. Never will stay there again.

Leon · 08-07-2021, 11:58 AM

I experienced this problem of smell even after black tank flush and empty the tank and the washroom still smell especially when going down the road.
So brought a garden hose inside the bathroom and sprayed down the toilet. Used quite a bit of water then when I drained it more brown crap came out and that fixed the problem no more smell afterwards

GraftonGuns · 08-07-2021, 01:13 PM

Not enough water to break down the solids. Flush like you are home. We use happy Camper and copious amounts of water. When ready to dump the tanks, I fill them with fresh water till full then dump. No problems or stink in 5+ years.

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