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Holding Tank Odor

Yahoo Message Number: 100474
Subject: Holding Tank Odor

We have a 2007 Magna 45'.  We bought it new. For years, we have had black water tank odor off and on.  Mostly when we are in motion, but not always. We have tried everything we can think of and then some, but the problem persists.
 Most recently we had the tank power flushed to assure the tank itself was clean. Dan at Healthy Tanks did it on site here in Orlando, and I watched the process.  The water coming out at the end of the cleaning was perfectly clear.
 We are sure the vent thru the roof is clear.  The toilet will hold water, so the flushing seal should not be the problem.
 I had a new floor mounting seal put in three years ago.  Possibly this may need to be replaced again. I'm told it is rubber.  Maybe replace with double wax ring?  Possible ?
 Now we are sitting still, and there is no problem.  The tank is about 1/4 full.
 When we moved across the parking lot (we are in for service), the problem surfaced big time. Turning the vent fan on did not help.  In the past, turning it sometimes made things worse.
 I cannot say if wind causes the problem causing air flow in the vent pipe as I just never put two and two together.  I will be more observant when/if we get odor whole parked to see if there is a correlation if there is wind.
 We opened windows (A/C on) and the odor dissipated.  In a few hours the problem was gone.  24 hrs later there is still no problem.  Little or no wind today, and no physical movement. We have a finned directional rotating vent cover.
 We had been using Thetford chemicals, but switched to TankTechs Rx on the recommendation of Dan, the owner-operator of Healthy Tanks here in Orlando.  I don't think this is the problem, tho others might not agree.  We have tried other chemicals and 'home brews' to no avail.
 My theory is that the odor is escaping from under the toilet and that the floor seal is the culprit.  The base of the toilet is about 1/8"!off the floor.  To test my theory, I am going to put masking tape around the base and seal it off to see if that solves the problem.  Don't want to seal with silicone as that would be tough to get off if necessary, plus if there is a leak under there, it has to be fixed first.
 I know this is a long write up, but I felt that I may as well try to answer questions that would obviously come up.
 Any assistance or ideas would be appreciated. Surely I am not the only one having this problem.

Bob Fuzak

'O7 Magna 6827M
'08 Honda CR-V

Re: Holding Tank Odor

Reply #1 –
Yahoo Message Number: 100475
When we are in motion and any windows are open we do get the smell inside the coach. All the windows and vents must be closed when we're moving.  We don't flush if the vent fan is on.  We use Thetford Campa Chem and use 2 small bottles or whatever the measure says on the large bottle depending on the size of our tank. When the weather is extremely hot we may have to use more.

So far this is what works for us.

Please keep us posted on your findings.

Lonny & Diane Livingston
'04 Allure #31065

Re: Holding Tank Odor

Reply #2 –
Yahoo Message Number: 100478
If you do not use the clothes washer the trap my be dry and the odor can be quite significant 06 intrigue. 12047. Bob

Re: Holding Tank Odor

Reply #3 –
Yahoo Message Number: 100479
also close all the drains and see if that helps. Might be the check valves (airless vents) in the drains.

Lonny & Diane Livingston
'04 Allure #31065

Re: Holding Tank Odor

Reply #5 –
Yahoo Message Number: 100481
Order "Happy Camper" Toilet Powder Cleaner. That solved our problem.
D Jean
CC 81072

Re: Holding Tank Odor

Reply #6 –
Yahoo Message Number: 100483
I had to use something similar to the cyclone vent on 98 Allure, it worked well while moving, but then sometimes you could smell the odors outside the coach and would drift in with the windows open.  Then when I found Eco-Save  there was no real need.  Just pour in a couple of dipper full of product in the grey and black holding tanks and add water, the more water the better it works.  Then drain the tanks when almost full and repeat the process.  Carr industries sells the product, or you can order it straight from the makers in Santa Rosa, California.  Now that I have a closed black water system with a toilet that has a P-trap the only real  issue I have is the grey water which can sometimes allow odors to drift into the sink in the slide room as there is no vent stack.  So it's doubly important to use the Eco-save .  Eco-save either comes as a liquid  or dry.  I use the liquid to touch up the sink and shower P-traps at the beginning of each season, with the dry added after every drain interval.  I keep the tank drain valves closed all the time and usually drain on Sundays and Wednesdays.  You can also use it to clean sinks and deodorize toilets.  I use it on my tile floors.  If you buy their liquid concentrate, you mix it 8:1  for holding tank use and 16:1  for general surface use.  A bottle of concentrate and two jars of dry will last me a an entire season of travel. TWI 2004 Intrigue 11731

i'st

Re: Holding Tank Odor

Reply #7 –
Yahoo Message Number: 100484
Are you sure it is the black tank?  Grey tanks can get pretty rank themselves.

Larry Cannon

2008 Intirgue 122070

Re: Holding Tank Odor

Reply #10 –
Yahoo Message Number: 100490
Yup make sure all drains have water in the trap and the vent cyclone on both.

Ray O 
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Re: Holding Tank Odor

Reply #11 –
Yahoo Message Number: 100492
This is a repost of a posting I made in late 2006:

We had a black water odor problem in our 2007 Allure when we had a negative pressure in the coach (fans running without enough windows open) which we traced to the improper sealing of the pipe as it went through the roof.  It really surprised me.  Here is what was found:
 Holes are drilled through the roof for the vent pipes.  The roof is put on the coach, but sometimes the vent pipes are not long enough. Vent caps are attached, but, because of the short pipe, air is drawn into the coach, through the vent caps and down the larger roof holes, when there is a negative pressure in the coach. It doesn't take much sewer smell coming up the pipe to be drawn down the roof hole into the coach to smell in the coach.
 How long should the pipe be?  Long enough to go through the large hole AND through the TIGHT COLLAR in the vent cap base.  This blocks air, rain and sewer smell access to the hole in the roof.
 On two of my vents, the pipe was a 1/2 to 3/4 inch too short.  Just take off the vent cap and see if the collar in the vent base TIGHTLY seals the pipe.  If it doesn't, since it is difficult to extent the pipe just a little, it is necessary to remove the vent cap base, seal the gap between the larger roof hole and the vent pipe (putty tape and then sealant), reinstall vent base, and cap.

No more smell, in our case.

Also, try my Drakkar test!!!  Sprinkle some Drakkar after-shave lotion down and/or around the vent pipe on the roof, and then sniff in the coach.

Herb

2007 Allure #31466
Forum Moderator

Re: Holding Tank Odor

Reply #12 –
Yahoo Message Number: 100494
Here's a really good explanation of how tank odors mayget into the coach. Assuming the tank itself has not been breached/cracked/damaged in some way and the toilet is working properly, about the only way odor can get into the coach is from the vent pipe. It's possible that some quirky vortex of air movement could draw odor up through the vent pipe, out above the roof, and then circulate it back into the coach through an open window or door. That's not very likely though.
 It just about has to come from a vent pipe that goes from the tank to the by way of the coach interior. The other possibilities like dry P-traps should have been the first things eliminated if this is a recurring or persistent problem.
 All that said, the odor will enter the coach from a damaged vent pipe or a faulty "Air Admittance Valve" (AAV). The link below goes into some detail about the AAV. Most decent quality RV's have them and they do fail.
 Troubleshooting Sewer Smell in RV

Look in cabinets/vanities near sinks and toilet for the ones in your coach. Google "Air Admittance Valve" for sources and descriptions.

FWIW

Dave M. 2002 Affinity #6103
Dave & Cathy M, 2002 Affinity #6103, 2018 GMC Acadia, Linux Mint 19.2

Re: Holding Tank Odor

Reply #13 –
Yahoo Message Number: 100509
I had the same issue and eventually put in a wax ring to seal toilet to floor and no more odors.

Larry 03 Allure,  30856

Re: Holding Tank Odor

Reply #14 –
Yahoo Message Number: 100520
Bob,

Check your batteries. I once had one go bad and what I thought was holding tank turned out to be the battery.

Alex Ritchey

2000 affinity 42' tag B&B


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Re: Holding Tank Odor

Reply #15 –
Yahoo Message Number: 100527
The source of odors is often from either one or the other, or both, of the grey or black tanks. We empty both tanks pour Calgon bath crystals and water into each tank then drive awhile to wash the tanks out. The crystals make the tanks so slippery that soon nothing adhers to the tank to cause odors. We leave the mixture in until the next empty, then repeat. Lots of people recommend clorox and other mixtures but we haven't found that necessary. Try it, it works and is inexpensive. Barrie Boas 94 Concept 5111

Re: Holding Tank Odor

Reply #16 –
Yahoo Message Number: 100538
Bob, under each sink in the coach is a plumbing vacuum breaker.  They fail and you have a sink you swear is black water but is really gray tank.  Replace them all at about $5 each.  Alternative is your washer drain.  If you are not using the washer the trap will dry out and smell something awful.  I pour water down the laundry drain before travel after a long time in storage.

Good luck.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: Holding Tank Odor

Reply #17 –
Yahoo Message Number: 100540
Probably not you toilet seal but maybe.  You can tell if it is the trap vents by running an exhaust vent full throttle for awhile with all windows closed and then stick you nose under all the sinks if you have a strong smell under there it is one or more of your trap vents which is a common problem.  Also stick your nose around the washer if you have one if not did they leave the washer drain open?  could be the trap is dry put some water down the drain.

I just recently found another reason for smell..  I replaced our bathroom faucet along with the drain and stopper.  This one has square holes just under the stopper for returning water from a sink overflow.  Mine was full of stinky crud and was emitting slight but ugly orders whenever we drove down the road or ran water into the sink.  I washed out the holes as best I could and then shoved baking powder into those holes followed by white vinegar which I let sit for 1/2 a day.  And that cured the last of my problems.

next I will get a new drain tube without the square holes..

Hope this helps.

Rich O.

with another brand.

Re: Holding Tank Odor

Reply #18 –
Yahoo Message Number: 100544
Bob,

I have been trying to find the Calgon crystals for several years now without any luck. Where are you finding them?

John

'06 Inspire Da Vinci #51905

Re: Holding Tank Odor

Reply #20 –
Yahoo Message Number: 101064
The vent for the black tank is on the roof and is sometimes forward of the bathroom roof vent if the vent is open and windows in the motor home are open going down the road it will create a negative pressure inside and pull the odor inside. carl