Toilet smell

Purchased a MS 34 T two years ago. The toilet had a smell when flushed.
The smell got better briefly when I back flushed the raw water intake with a hose. When smell returned I changed the raw water intake hose. This stopped the smell for about 6 mo. but has now returned. Since purchase I have been in fresh water if that makes a difference. I assume the smell is coming from the walls of the raw water hose. Is there a hose with a special lining to prevent a smelly substance from attaching to the hose walls etc. Help!

Keith, do you notice any difference in the smell between the first flush when you go to the boat vs after a couple of flushes when the boat is being used?

If it smells bad by the head after the first flush and then gets better it is from the stagnant water sitting in the water intake hose from the seacock to the head. The real fix is to go to a freash water flush head. The micro organisms die while sitting in the intake hose due to lack of oxygen then they decay ans start to smell. If the smell is coming out of the holding tank vent then the cause is usually lack of oxygen in the holding tank. Remove any filter in the vent hose and try to get more air into the tank and the smell will go away when it has enough oxygen.

MS 34Ts are notoriously bad for smelly holding tanks due to poor ventilation.
I just did a head rebuild w a impeller / seal kit. Took the whole unit home to flush it well. I was amazed at how much "stuff" came out of the inlet hose and the bowl rim and we are also in fresh water.
I used to get a smell at the head after flush but believe it was at least partially from the holding tank as we could hear s gurgling after flushing and assume the poor vent allowed some tank pressure to push vapors back to the head.
I switched to NoFlex and added a tank bubbler and it made a huge improvement. During layup I figured out how to run a larger / straighter vent from bow to holding tank. Anxious to see if that helps even more.

Your description of the problem sounds like the problem is originating in the toilet intake line. This should eliminate odor from it: Remove the intake line from the thru-hull (close the seacock first!) and stick it into a bucket of water to which you've added a quart of distilled white vinegar. Flush the entire bucketful through the toilet.

If that doesn't do the trick and especially if you see black flecks in the flush water coming out the rim of the bowl, there has to be some dead and decaying animal or vegetable sea life trapped in the hose or possibly in the channel in the rim of the bowl. Best solution for that will be a new intake hose. A plain ol' Shields or Trident flex PVC (the least expensive sanitation hose) will be fine for this--and btw, the size needed is 3/4". If you continue to see black flecks in the bowl after replacing the hose, the culprit is in the channel in the rim of the bowl...it needs to be flushed out with water under pressure (garden hose nozzle is enough). Unless you want water all over the head, 'twould be a good idea to remove the bowl and put it on the dock to do this. You'll need to replace the bowl seal--which you can get from the toilet mfr--if you don't want it to leak when you put it back.


--Peggie

Sorry about toilet spelling. The smell does get a little better after several flushes. I am going with Peggy's idea. Much less work than a hose change which was a temp fix. Also I can remove the tank filter to try that. Thanks for all the suggestions!!

Bacchus, it's usually a simple matter to modify the tank venting to allow more air exchange. Shortening/straightening the vent line, replacing the vent thru-hull with an open bulkhead thru hull, even "upgrading" the vent from the standard 5/8" to 1" or even 1.5" has become a fairly easy job on most tanks thanks to a little gadget called the Uniseal UNISEAL. Every boat is different, even different model years of the same boat, so I won't post "boilerplate" instructions, but I'll be glad to help you or anyone else figure out how best to do it on YOUR boat if you want me to.


--Peggie

If you remove the toilet, you might flip it over and immerse the rim in a vat of white vinegar for a day or two before flushing with rim with fresh water.

HeadMistress said:

Bacchus, it's usually a simple matter to modify the tank venting to allow more air exchange. Shortening/straightening the vent line, replacing the vent thru-hull with an open bulkhead thru hull, even "upgrading" the vent from the standard 5/8" to 1" or even 1.5" has become a fairly easy job on most tanks thanks to a little gadget called the Uniseal UNISEAL. Every boat is different, even different model years of the same boat, so I won't post "boilerplate" instructions, but I'll be glad to help you or anyone else figure out how best to do it on YOUR boat if you want me to.


--Peggie

Click to expand...

I did those on a previous boat but Mainship did a very poor job of routing & connecting vents. I have an access plate in the area of fuel fill and FW, fuel & holding tank vents. Only problem is all hose clamps were installed prior to assembling hull to deck and clamps are now "backwards" and screws hidden/unaccessible.
I finally abandoned the holding rank vent and left it in place. Then ran a new, larger hose to a straight thru hull vent placed near the bow so the run is pretty straight to the tank.

I installed masterflush fresh water toilets and eliminated the Y valve. Then I repurposed the direct overboard hose to an additional vent for the holding tank. With no quantitative evidence, it seems that everything is working better. No stink at the toilet, pumping out seems faster.
Thanks Peggy!

Comodave said:

If it smells bad by the head after the first flush and then gets better it is from the stagnant water sitting in the water intake hose from the seacock to the head. .

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I had this problem (Brackish water here). A couple of 1" Bromine tablets in the strainer from a Pool/Spa store (or Amazon) completely cured the problem..

Heron said:

I had this problem (Brackish water here). A couple of 1" Bromine tablets in the strainer from a Pool/Spa store (or Amazon) completely cured the problem..

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Bear in mind you want to limit any exposure of plastics to that stuff. It'll weaken most plastics if they're not designed to be exposed to bromine. This I know from taking ownership of a hot tub that the previous owner misused bromine in it. More is not better.

This holds true for all kinds of cleaners and such when it comes to the fiberglass, plastics and vinyls found in boats. What "works" today turns out to be a nightmare down the road when it causes the materials to fail because of leaching out the things that made the materials work. Always check that any products you use are actually safe for the materials.

Plastic Hot tub jets very sensitive th Ph... I swear they make them intentionally that way to be a replacement item as other plastic parts in the jets are OK. One piece fails... toss & replace

Bacchus said:

Plastic Hot tub jets very sensitive th Ph... I swear they make them intentionally that way to be a replacement item as other plastic parts in the jets are OK. One piece fails... toss & replace

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While planned obsolescence is always a factor, truth be told it's difficult to make plastic pieces cost-effectively that'll withstand constant immersion in treated hot water. Sure, for lab and factory setups there's options but those are seriously expensive; more than the market will bear for residential hot tub installs.

I thought it was chlorine bleach that was bad for plastic and bromine that was benign.....?

CLORINE is destructive to rubber as well as plastics...and bleach (sodium hypochlorite) isn't the only type of chlorine...halogen is one, bromine is type of halogen. Hypochlorous acid is yet another type of chlorine. An occasional dose of any of 'em not left in the system very long is one thing, but a "steady diet" of any of 'em is not only destructive to plastics, but highly destructive to rubber. So I'd remove the bromine tabs from your intake strainer and use a bucket of water to which a quart of distilled white vinegar has been added to clean out your intake hose and bowl channel as needed. Or upgrade your toilet to one designed to use pressurized fresh water. Both Raritan and Jabsco offer "conversion" kits that replace everything south of the bowl.



--Peggie

Lots of comments on venting the waste holding tank. Very important to install a vent to both port and starboard side. This allows cross ventilation and maintains good levels of oxygen in the tank.

Regards

Marangal said:

Lots of comments on venting the waste holding tank. Very important to install a vent to both port and starboard side. This allows cross ventilation and maintains good levels of oxygen in the tank.

Click to expand...

Unfortunately, most of us are stuck with what the builder did to begin with. Mine has one vent line that is too small, too long, and had a cowled fitting on the hull. Very common. I have changed the hull fitting to just a simple open mushroom but of course it would be idea to increase the size of the vent line as well as add another one on the opposite side of the boat. However, it would be a pretty challenging task on my boat.

It was frankly much easier (and likely cheaper) for me to add a bubbler to the holding tank for an O2 source.

As Peggy said, with an Uniseal, two larger diameter vent line can be added to almost any holding tank made of plastic or metal. Ports can be bonded to fiberglass. I prefer spin welding fittings to poly tanks but that is dependent on router access to the tank.

Uniseals are very reliable for a long time.

dhays said:

Unfortunately, most of us are stuck with what the builder did to begin with. Mine has one vent line that is too small, too long, and had a cowled fitting on the hull. Very common. I have changed the hull fitting to just a simple open mushroom but of course it would be idea to increase the size of the vent line as well as add another one on the opposite side of the boat. However, it would be a pretty challenging task on my boat.

It was frankly much easier (and likely cheaper) for me to add a bubbler to the holding tank for an O2 source.

Click to expand...

A bubbler will do the job extremely well. Have done it on a previous boat with great success.

Even though the bubbler works effectively and is pretty low wattage, I ended up taking mine out when we started anchoring for longer periods.

Large diameter vents on opposite sides of the boat increase air flow significantly through the holding tank. I have'nt encountered many boats whose holding tank could not be retrofitted with additional vent fitting.

Coincidentally, Peggy Hall, we started retrofitting holding tanks with additional larger vents after you suggested that on the Mainship Forum in the mid 90's. You should have patented it.

You were a big contributor on that forum back then.

syjos said:

Even though the bubbler works effectively and is pretty low wattage, I ended up taking mine out when we started anchoring for longer periods.

Large diameter vents on opposite sides of the boat increase air flow significantly through the holding tank. I have'nt encountered many boats whose holding tank could not be retrofitted with additional vent fitting.

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Not saying it can’t, just that it would have been much more work than I was willing to put into it. I also agree that adequate ventilation with vents is a much better solution than a bubbler.

The bubbler works great and the amp draw is very low and it is very quiet. Even so, it does draw <.5 amps. Small draw but when on 24 hours that does add up. Quiet does not mean soundless. It is an electric pump that will eventually fail and need to be replaced. Vents take no electricity, are soundless, and don’t wear out over time.

Yes, ventilation by passive means is the ultimate solution but in many boats it is physically impossible. My current boat would be a candidate for a bubbler system if I do get smells venting out of the tank, thankfully there is no current problem. But if the smell does start, I will go with a bubbler system.

I can strongly recommend going with Peggy's advise/plan I had exactly the same problem only additional thing I did was to put an inline filter between the sea cock and the Dunny (Kiwi for toilet!!!) that was some months ago now and all good with the exception that on some occasions the first flush pongs if we have not used the boat foe a while. Peggy is the "Holy Grail" of Dunnies!!!!!!!!!!!!!!!!!!!!!!

Comodave said:

If it smells bad by the head after the first flush and then gets better it is from the stagnant water sitting in the water intake hose from the seacock to the head. The real fix is to go to a freash water flush head. The micro organisms die while sitting in the intake hose due to lack of oxygen then they decay ans start to smell. If the smell is coming out of the holding tank vent then the cause is usually lack of oxygen in the holding tank. Remove any filter in the vent hose and try to get more air into the tank and the smell will go away when it has enough oxygen.

Click to expand...

You nailed it. My boat, which currently sits in a river, has a seawater foot pump for the galley sink. If that pump and the toilet aren't used for a couple of days, the first several pumps of water will stink almost as bad as the inside of a holding tank. After that it's fine, so the smell is definitely from dead stuff in the raw-water line. This is just part of life afloat -- like "boat farts."

dhays said:

Unfortunately, most of us are stuck with what the builder did to begin with. Mine has one vent line that is too small, too long, and had a cowled fitting on the hull. Very common. I have changed the hull fitting to just a simple open mushroom but of course it would be idea to increase the size of the vent line as well as add another one on the opposite side of the boat. However, it would be a pretty challenging task on my boat.

Click to expand...

That was true of the setup on our old boat. Undersized hose and terrible routing. It never stood a chance of ever working properly. But it was such an on-going hassle that I really should have tackled it. It's one of those things that risks rising to the level of the "wife hates the boat" problems.

On our current boat the design is better but the hose had developed a dip, allowing moisture to settle and effectively become a trap, blocking any air from flowing past. I was fortunate that the location of the dip was accessible and easy to fix using some cushioned hose straps. I also thoroughly flushed the line with fresh water and let it dry for several days. Once I raised and secured the hose to prevent the dip the tank smells all but disappeared.

Phil23 said:

I can strongly recommend going with Peggy's advise/plan I had exactly the same problem only additional thing I did was to put an inline filter between the sea cock and the Dunny (Kiwi for toilet!!!) that was some months ago now and all good with the exception that on some occasions the first flush pongs if we have not used the boat foe a while. Peggy is the "Holy Grail" of Dunnies!!!!!!!!!!!!!!!!!!!!!!

Click to expand...

Should Peggie have a Down Under moniker- “DunnyQueen”?

syjos said:

Even though the bubbler works effectively and is pretty low wattage, I ended up taking mine out when we started anchoring for longer periods.

Large diameter vents on opposite sides of the boat increase air flow significantly through the holding tank. I have'nt encountered many boats whose holding tank could not be retrofitted with additional vent fitting.

Click to expand...

Often just replacing the existing vent line with a shorter, straighter larger diameter vent line can make it unnecessary to add a second vent...

[/QUOTE]Coincidentally, Peggy Hall, we started retrofitting holding tanks with additional larger vents after you suggested that on the Mainship Forum in the mid 90's. You should have patented it. You were a big contributor on that forum back then.[/QUOTE]

Thanks for the compliment! But I don't think it's possible to patent "use a larger hose."

[/QUOTE]On our current boat the design is better but the hose had developed a dip, allowing moisture to settle and effectively become a trap, blocking any air from flowing past. I was fortunate that the location of the dip was accessible and easy to fix using some cushioned hose straps. I also thoroughly flushed the line with fresh water and let it dry for several days. Once I raised and secured the hose to prevent the dip the tank smells all but disappeared. [/QUOTE]
Wouldn't it have been simpler just to shorten the vent line enough to eliminate the sag?

[/QUOTE]Lots of comments on venting the waste holding tank. Very important to install a vent to both port and starboard side. This allows cross ventilation and maintains good levels of oxygen in the tank. [/QUOTE]
You're correct that the key to odor elimination is prevention and oxygen is essential to prevention. However, It's not always necessary to cross ventilate...a single large diameter vent can often work just as well--sometimes even better. It can even be as simple as replacing the "vent" thru-hull with an open bulkhead thru-hull. There are some installations--tank buried deep in the bilge and/or installed on the centerline with too much "stuff" on either side to allow a short straight relatively horizontal run--that won't allow cross ventilation to work..when aeration is the only good solution. Iow, there is no single "carved in stone" solution to holding tank odor on every boat.

And I thank all of you for all the kind words here about my efforts to help you find the right solutions for your boats.

--Peggie

HeadMistress said:

On our current boat the design is better but the hose had developed a dip, allowing moisture to settle and effectively become a trap, blocking any air from flowing past. I was fortunate that the location of the dip was accessible and easy to fix using some cushioned hose straps. I also thoroughly flushed the line with fresh water and let it dry for several days. Once I raised and secured the hose to prevent the dip the tank smells all but disappeared.

Click to expand...

Wouldn't it have been simpler just to shorten the vent line enough to eliminate the sag?

Click to expand...

Perhaps, but the run is relatively direct from the tank toward the vent on the hull. As it left the tank there was a stretch that wasn't supported very well and a dip developed. Not a lot but enough 'water' to collect and block airflow. Now it's clear and better supported to prevent the dip from returning. It's likely over the next winter I'll replace the various head drainage lines, this one included. Assuming that I find access to the back side of the hull vent, that is. Everything else appears to be 'reasonably accessible'.

And I thank all of you for all the kind words here about my efforts to help you find the right solutions for your boats.

--Peggie

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The compliments are deserved, you've helped quite a lot of boaters and our guests with your sage advice.

Phil23 said:

Peggy is the "Holy Grail" of Dunnies!!!!!!!!!!!!!!!!!!!!!!

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Not disputing it, in the least. Peggy's the bomb!

But that phrase is funny! :lol: