Black Tank Smell

[PSU1981]

We have not camped for about a month & when I got it out of storage I've got a horrible smell coming from the black tank. I know I emptied it before storage - but tank monitor says black is 20% full?? I will not be near a place to dump until tomorrow. I have put in 2 TST RV toilet treatment drop ins & ran some water thru the toilet. Anyone have any other cure for this smell.

Thanks,

Glenn
Spring, Tx
2015 27FB Flying Cloud

[Protagonist]

It's possible that the tank wasn't completely empty. RV tanks tend to be wide and flat, and dump best if the trailer is tilted so that the street side is higher than the curb side, so that everything in the tank runs to the side with the drain. If the trailer was level when you dumped it, some of the liquid and/or solids might not have drained.

Clean water will not stagnate, but water that contains organic material— such as in a black tank— can stagnate if left undisturbed.

If you can dump it tomorrow, fill the tank close to full, and make sure the trailer is tilted slightly to the street side when you dump.

[Sbb]

add some ice cubes in morning before you go, drive around and let them scrub around as the melt to help get a good cleanout.

[A W Warn]

Assuming you are not talking about a bad smell when you flush the toilet; There should be no smell inside if everything is working properly, even if there is stinky stuff in the black tank.

If you are talking about smell when you open the valve in the base of the toilet to flush, make sure the vent fans are turned off, or are blowing inward. Exhaust fans blowing inward push the fumes back through bowl and out the roof vent instead of letting it escape inside. Fans turned on exhaust, blowing outward, can pull those fumes up through the toilet into the interior.

One test to find a leaking problem with the toilet bowl is to pour some liquid in the bottom of the bowl. If the liquid remains in the bowl, you know no foul fumes are escaping through there. (one of my toilets has a worn seal, so I deal with this occasionally)

I know some bathroom sinks dump into the black water tank instead of the gray water tank, but I'm not sure which Airstreams are built this way. If the liquid in your sink trap has evaporated fumes might come inside through the sink trap. You can put your nose close to the bathroom sink drain to sniff at that specific location. If that is the issue, just add some liquid to the sink to fill the trap. A foul smell could come from the gray tank, so check the kitchen sink trap and the shower trap.

Look for open exhaust vents near the black tank vent where it penetrates the roof. If there is an open vent and wind is blowing just right to create a slight negative pressure inside, those vented fumes can come inside through the vent.

If one of the above is not found, there could be an improperly sealed sewer pipe or the foam gasket between the toilet bowl and toilet flange could be improperly installed.

I'm betting one of the traps is dry, letting foul fumes pass.

[Cannonball]

Dump in a cup of bleach. Drain at your next stop.


Cannonball, Deep in the Heart of Texas!

WBCCI #4387, Air #84080

Sent from my iPad using Airstream Forums

[CRH]

X2 on bleach

[paiceman]

Actually it helps if the trailer is higher on the PASSENGER side and most dumps are set up that way. The dump connection is on the STREET side.

As suggested put a LOT of ice cubes in the toilet, drive to your next location and get a full hook up site. Then hook up sewer connection, fill the black tank all the way until you see water in the toilet coming up from the tank. Then start dumping and as you dump with the black tank washout hose hooked turn it on and let it run for a while. I let ours run for half an hour before I put it away for the winter. Then once all completed, close her up and add a couple of bottles of blue stuff. They also sell a long term storage solution you can add before putting it into storage. I've used it, never had a smell so I'm guessing it works.

[CRH]

There is a pretty good video on YouTube regarding the ice cube cleaning method.

[Protagonist]

Originally Posted by paiceman

Actually it helps if the trailer is higher on the PASSENGER side and most dumps are set up that way. The dump connection is on the STREET side.

Thank you for the correction. Another senior moment!

[paiceman]

Originally Posted by Protagonist

Thank you for the correction. Another senior moment!

Ha, daily occurrence-multiple times.

Bud

[idroba]

Originally Posted by CRH

There is a pretty good video on YouTube regarding the ice cube cleaning method.

The ice cube cleaning method is pretty well shot down in this well done You Tube video showing a test with a clear plastic tank.

https://www.youtube.com/watch?v=iH6acEmqvcw

[PSU1981]

Thanks everyone !!

[Protagonist]

Originally Posted by idroba

The ice cube cleaning method is pretty well shot down in this well done You Tube video showing a test with a clear plastic tank.

Intuitively, it's like a washing machine. Or should be.

It works better if you add detergent to reduce the surface tension of the water so it can soak in better. He didn't add detergent.

It works better if you add enough water during the wash cycle to cover everything that's dirty. He didn't add water until the rinse cycle.

It works better with an agitator than without one. Well, he had an agitator, in the form of ice.

Which means that the test in the video is not exactly conclusive evidence that the ice cube method is a myth. He could have added more water, added soap, and even more ice. (And he could have driven on bumpy, potholed New Orleans streets rather than a parking lot, to really churn up the water!) If he had, he might have gotten different results. Or he might not have. More testing is required. Accepted scientific and engineering practice suggests that a single test does not prove or disprove a hypothesis.

[Foiled Again]

Don't forget the GRAY tank while you're cleaning up either. There are always bits of food waste, dead skin cells, hair, and soap in the gray tank - and it can get it's own particular variety of "Whew factor"... that's as bad as the black tank in it's own way.

I full-time and don't have to consider the fermentation process that can grow and continue in the tanks. But I did go on a trip leaving the trailer hooked up for a week and even with the A/C on at a minimal level (set at 80 while gone) when I came back, the first use of the facilities was beyond unpleasant.

When storing for a week or longer, I second the idea of draining the tanks, rinsing them, then filling them adding some bleach, letting them stand for an hour or so, and then draining them dry. If you store for a long period, the toilet seal WILL dry out and so will the traps in the sink and shower. If you check them 3-4 times a month and add water the seal in the toilet will last a lot longer.

BTW, If you want to create "agitation" while draining the tanks why not use the electric tongue jack and create some wave action? Especially good if you use dish detergent in the rinsing process. Grease stinks badly too, and there are no sprayers in my gray tank, so two or three times a year I fill the tank 3/4 full of warm while squeezing in some Dawn, then create a sloshing motion and drain.

Paula

[Protagonist]

Originally Posted by Foiled Again

If you store for a long period, the toilet seal WILL dry out and so will the traps in the sink and shower. If you check them 3-4 times a month and add water the seal in the toilet will last a lot longer.

If you add water (or RV antifreeze, depending on the time of year) to the toilet bowl, you can slow down the evaporation process by covering the toilet bowl with Saran Wrap, taping it in place if it doesn't cling properly. Any liquid that evaporates out will condense on the Saran Wrap, and drip right back into the toilet bowl. Saran Wrap is a lot cheaper and easier to replace than a toilet seal…

Someone else here on the Forums suggested that; it's not an original idea of mine.

[dkottum]

We've found a generous coating of silicone grease on the toilet seals keeps it from drying and operating smoothly.

Wouldn't hot water and detergent be a good solution to clean the tank, cold water would seem to stiffen things up. On most late model Airstreams the bath sink also drains into the black tank. You can get 6 gallons of hot water into the black tank by running the bath sink hot water faucet, add detergent and let that slosh around in there while you travel from place to place.

[idroba]

Originally Posted by Protagonist

Intuitively, it's like a washing machine. Or should be.

It works better if you add detergent to reduce the surface tension of the water so it can soak in better. He didn't add detergent.

It works better if you add enough water during the wash cycle to cover everything that's dirty. He didn't add water until the rinse cycle.

It works better with an agitator than without one. Well, he had an agitator, in the form of ice.

Which means that the test in the video is not exactly conclusive evidence that the ice cube method is a myth. He could have added more water, added soap, and even more ice. (And he could have driven on bumpy, potholed New Orleans streets rather than a parking lot, to really churn up the water!) If he had, he might have gotten different results. Or he might not have. More testing is required. Accepted scientific and engineering practice suggests that a single test does not prove or disprove a hypothesis.

But the "Add a bag or two of Ice Cubes to the tank and drive around and all will be great" is what is always stated as if it is fact. This You Tube video at least attempts to show that it may not be, with a real test, not "intuitively"

You equate the ice cubes in the tank as if it were a washing machine. It is not. Only "intuitively".

Have you looked at a new top loading, no center post washer, the ones which are on the market now? They don't add enough water to hardly wet the clothes. They have re thought the washing process, and done engineering tests apparently and have found that a huge amount of water is not needed to wash clothes. It is amazing how little water is needed to run a cycle in today's washers.

Unfortunately intuition of how things should work is not the engineering way. It is a guide for further study, but not a proof of fact.

The You Tube video is at least a decent attempt to prove or disprove the ice cube cleaning of black tanks claims. In my engineering mind it is far better than an Intuitive justification.

We need a 10 million dollar government sponsored research program to find the truth.....Do ice cubes in an RV tank really clean them? LOL. But even then the results will be challenged by someone who does not like what they find.

[xrvr]

If you were plugged in it might be the batteries you are smelling.

[CRH]

Originally Posted by dkottum

Wouldn't hot water and detergent be a good solution to clean the tank, cold water would seem to stiffen things up. On most late model Airstreams the bath sink also drains into the black tank. You can get 6 gallons of hot water into the black tank by running the bath sink hot water faucet, add detergent and let that slosh around in there while you travel from place to place.

I often put dish detergent and a bit of my tanks at the beginning of the trip before I leave home. On the final day, I run the tanks nearly full with hot water and more detergent and let them sit while I am breaking camp down. When I dump the gray tank at the end, it always has a nice coat of suds left in it. I believed my practice is doing a bit to keep my tanks clean.

[kittmaster]

Originally Posted by A W Warn

......I know some bathroom sinks dump into the black water tank instead of the gray water tank, but I'm not sure which Airstreams are built this way.

Confirmed, my 2019 International RBQ does exactly this...bath sink drains into the black tank. I normally run water to ensure the trap isn't dry and prevents any odor.