Holding tank odor in cabin, after initial start up

M

mooredriven

New Member
Oct 16, 2006
76
Flower Mound, TX
Boat Info
340 Sundancer, 2003
Engines
8.1 Horizon's
I've researched this issue on the site but wanted to check with everyone else to see if they agree.

We empty the head every two weeks. The odor occurs between pump-outs, after waste from the previous week has been in the holding tank. I smell the odor almost immediately after turning on the head. The smell is not apparent in the head, but rather the mid-stateroom, with the toilet on the other side. I'll typically open the windows and door to clear the smell. Once removed, the smell does not return.

I suspect that when the pump is pressurizing the system, air is leaking through the duckbill valves, back to the toilet. My thoughts are to replace the four duckbill valves in the vacuum generator hoses.

It appears to be a simple system. Let me know if agree or if I'm missing something.

Thanks,
Dale

P.S. I'm confident the vent filter is good and the line is clear. I've had a bad/wet filter before. At that point, the cabin always stinks. I also ensured the vent line is clear this weekend, which could have caused an issue.

I use Odor-Loss tank treatment, which has performed best in our hot Texas summers.
 
I don't think the duckbills would cause an odor. It operates by creating vacuumn which would draw air into the toilet. I've heard in the past the sewage lines can become permeated with the smell thus releasing it into the cavities in which they run. Being an '03 seems a little early but I guess not impossible. I would search out the line from the toilet to the pump and see if it smells.
Also I've never had to use a holding tank treatment so long as the charcoal filter was in good working odor. I've always been baffled by people that do and to me wasting money.
 
I wanted to provide an update to my initial post. I replaced three of the four duckbill's. I couldn't get one of the threaded PVC pipes off without damaging it. It was on the output of the pump, so I wasn't as worried about it being the cause of the issue.

The smell still exists. I may replace the hose next, but plan to call Domestic next to get their opinion. A doc neighbor has a similar problem, but he doesn't have a Vacuflush system. He's replaced his ducbill's and hose. He still has the odor.

I'll update as I continue to try different options. Maybe this will help someone else later.
 
Did you change out the
8346.jpg
or something that looks similar. About $100.
 
If it's not the hoses, it could be sludge in the bottom of your holding tank. When you pump out most of the liquid is gone and for whatever reason the smell seems to be greater at this time. Once you flush once, the air is expelled out of the tank and it typically smells worse. Usually after I pump out, I put in a little tank cleaner/deodorant and the smell is gone until the next pump out.

Doug
 
Bad duckbills are not going to cause an odor. They are inside of a sealed system.

I guess I have a few other questions before I can give an educated guess.

1. Does the toilet hold a vacuum? If it does, then you have eliminated everything in between (and including) the toilet and the first set of duckbills. Since this "odor" is not constant, I would not think it is the hoses anyway...

2. Is there any wetness from the bellows pump to the tank? Check all the connections for leaks and loose clamps or cracked hoses between the vacuum tank and holding tank... You may have a cracked hose or loose clamp.

3. One other area is the the bellows. This is the do-dad on the vacuum tank that goes up and down. It is in between the duckbills. It has a rubber seal on it to keep stuff from coming out the top when in pumps. Check that for dampness and if that seal is bad, get a replacement... that would cause a smell as you describe... but check #2. <- (that's damn funny right there) If you've ever put bleach down your toilet, not only can you damage the duckbills, but the bellows seals as well...

4. Check all the connections on the top of your holding tank (like if you have a macerator) including the deck pump out connections, etc. Check the hoses for cracks as well.. it's possible if you have a loose clamp on something like your pumpout connection (or a cracked hose), the system is out-gassing through this leak and not the filter/vent.
 
Last edited:
Thanks to everyone for their responses.

r_moss - I'm certain the filter is good because in the past, when I had a bad filter, the smell would remain all day. I learned the hard way about this when I first got the boat.

StephenOvalle - thanks for the article. I'm not sure what a "nitrate treatment" is, but I'm willing to try it. We have a good gas dock attendant that flushes out our holding tank a few times, until there is clear liquid. Then usually once more for good measure. Last year I used a holding tank cleaner, don't remember the brand, that I purchased from West Marine to clean the tank. I thought it would help, but did not.

douglee25 - I always add Odorloss, or more recently KO, to the tank after we get a pump out. Both are bacteria based.

Four Suns, answer to your questions.
Four Suns said:
1. Does the toilet hold a vacuum? If it does, then you have eliminated everything in between (and including) the toilet and the first set of duckbills. Since this "odor" is not constant, I would not think it is the hoses anyway...
Click to expand...
Yes.

Four Suns said:
2. Is there any wetness from the bellows pump to the tank? Check all the connections for leaks and loose clamps or cracked hoses between the vacuum tank and holding tank... You may have a cracked hose or loose clamp.
Click to expand...
I didn't notice any wetness, around or on the tank. I did tighten all of the hose clamps a few weeks ago, but didn't do a thorough job of checking for cracks.

Four Suns said:
3. One other area is the the bellows. This is the do-dad on the vacuum tank that goes up and down. It is in between the duckbills. It has a rubber seal on it to keep stuff from coming out the top when in pumps. Check that for dampness and if that seal is bad, get a replacement... that would cause a smell as you describe... but check #2. <- (that's damn funny right there) If you've ever put bleach down your toilet, not only can you damage the duckbills, but the bellows seals as well...
Click to expand...

I agree that the bellows may be the issue. I've never poured bleached directly into the system, BUT, when I sanitize the water tank in the winter, it's possible some diluted bleach may have entered the holding tank.

Question: If the bellows are the issue, wouldn't you expect the smell after each flush? The smell only occurs, in between pump-outs (bi-weekly) and at start up.

Four Suns said:
4. Check all the connections on the top of your holding tank (like if you have a macerator) including the deck pump out connections, etc. Check the hoses for cracks as well.. it's possible if you have a loose clamp on something like your pumpout connection (or a cracked hose), the system is out-gassing through this leak and not the filter/vent.
Click to expand...

I plan to check these again this weekend. I did make sure that the vent hose from the filter to the side of the boat was clear. We have dirt dobbers that make mud nest anywhere there are openings.
 
Flush the lines a lot after you tie up the boat with fresh water. You don't want to marinate the hose in "stuff". Pull a panel if you need to, wipe the discharge hose with a clean damp rag, smell it, and if that is your stink you should replace the discharge line.
Like I need to do on my 1995.
 
UPDATE Re: Holding tank odor in cabin, after initial start up

I replaced the hose from the head to the tank and cured the issue. Unfortunately I didn't take any photo's of the hose, but the hose was dry-rotted where is passed into the cabin from the engine room. You could see wires exposed. I'm surprised the hoses didn't last longer, as the boat's only 7-years old.

The total time it took to replace the hose and put the toilet back together was 3.5 hours.
 
You must log in or register to reply here.

Forum statistics

Threads
113,186
Messages
1,428,170
Members
61,097
Latest member
Mdeluca407
Back
Top