Holding Tank Oder

[coyote848]

Last year I purchased a 1995 2859 Super Classic and when you flush the toilet the aroma is pretty bad and lingers for too long. Any recommendations on what to put in the tank to control the after flush stink?
I have tried the liquid from our local marine store but does not come close to neutralizing the awful smell. I am seriously thinking about replacing the tank but imagine that would be quite a process. Any suggestions would be gratefully appriciated, thanks, Ron

[Dstancil]

Hello Ron:
There are many more experts than me on this but I have the following advice since I own a very similar boat. You may need to change your hoses, assuming they are the original black ones as mine were before I had them changed. Also, check your holding tank vent. When you pump out the holding tank, you can try to always filling your tank after the pump out with fresh water and then pump out again. Here at my marina, there are water hoses by each pump out. Also, you can periodically add a little liquid laundry detergent, no bleach, and let it slosh around before you pump out. I use a powder, No Flex Digestor, between pump outs. Finally, you should visually check your holding tank by getting in the mid birth and tanking out the wall panel and just take a look to be sure there is no leakage. We have also found that if you flush with fresh water, it helps hold down the ordor. our boats were not designed with a fresh water flush for the head, but we just keep a couple gallons of dock water in the head in used water bottles.

[coyote848]

Hi Dave, I sure appreciate your advice on what to do. The man I bought the boat from told me he had the odor problem and that he changed "a" hose. So thinking about it there must be 3 hoses am I right?
I live in Maine and my boat is under wraps for the winter and am waiting for a little warm up before I start investigating this problem. I do have a couple 5 gal fresh water jugs that I could use to flush with if it comes to that option. When flushing the toilet the smell is just as bad as when pumping out.
Also very interesting on using liquid laundry detergent.
I'm glad that I found this Bayliner Owners Club, its very helpful to us all.

[Car2n]

Get a vent filter too. Look at Big Orange filters.

[floatyerboat]

Coyote,
Please check to make sure your vent to the tank is not plugged. Several years ago I chased the same problem. In my case I changed the hoses with no luck only to find out the previous owner neglected to pump out the tank and the poop backed up thru the vent and solidified. I didn't find this out until I installed a new electric flush head and noticed the square plastic holding tank inflated up like a basketball. The air had to go somewhere whether it be through the bowl or a fitting.
If the vent is plugged the air has to escape somewhere if the tank is compressed.
You might get lucky and find out a mud dauber just sealed your vent shut and as long as your at it check the vents on your fuel tanks too.

Winter Sucks

[coyote848]

Dan I ran into this blocked vent on my gas tank when filling it blew back out the filler pipe blocked by a mudder, thanks

[MerlinV]

As mentioned above, I strongly recommend Noflex Digestor. This product will ultimately remove the odors from your sanitation system, and will open up partially blocked hoses with regular use. We were planning to replace all of the sanitation hoses when we first purchased our boat five years ago, as ‘that odor’ had permeated right through everything aboard. Changing these hoses on a 5788 is a big job, and as we had used Noflex with success on previous boats, we had little to lose by using it again before starting in on an awkward and unpleasant job.

After pumping out the holding tank, we used a cap full of Noflex for every second flush of each head, and each time we left the boat, gave both heads another cap full for good measure. We quickly consumed two full containers of Noflex and then changed the use to one capful for each head for every day we were on board.

We never did change the hoses, and even today there’s no sign of the delightful head or holding tank odor - you may wish to try this stuff.

https://marinesan.com/noflex-digestor/

[carguy]

As mentioned above, I strongly recommend Noflex Digestor. This product will ultimately remove the odors from your sanitation system, and will open up partially blocked hoses with regular use. We were planning to replace all of the sanitation hoses when we first purchased our boat five years ago, as ‘that odor’ had permeated right through everything aboard. Changing these hoses on a 5788 is a big job, and as we had used Noflex with success on previous boats, we had little to lose by using it again before starting in on an awkward and unpleasant job.

After pumping out the holding tank, we used a cap full of Noflex for every second flush of each head, and each time we left the boat, gave both heads another cap full for good measure. We quickly consumed two full containers of Noflex and then changed the use to one capful for each head for every day we were on board.

We never did change the hoses, and even today there’s no sign of the delightful head or holding tank odor - you may wish to try this stuff.

https://marinesan.com/noflex-digestor/

I was going to post this as well. It's also as important to make sure the filter is clean as that allows air into the holding tank which activeates the microbes.

[randygh]

I have used No Flex digestor crystals in two boats' holding tanks. 26' Carver Monterey and 2859. When purchased, the tanks didn't stink, but I wanted to remove any residual debris in the bottoms. After unwrapping your boat this spring, I would fill the holding tank with fresh water from the deck pump out fitting and toilet. Pour No Flex down the deck fitting before filling. Don't skimp on the No Flex. Use at least a qtr cup of crystals through both the deck fitting and the head. Fill the deck fitting with enough water to have water flow out the vent line. Let the No flex set for at least 72 hours. Pump out the holding tank and repeat to be sure the vent line is patent and odor is no longer present. Swapping out the line from the head pump to the holding tank would be a real job. While boating, I daily pour about a tablespoon of No Flex in the head each day. We have absolutely no sh--ty odor in the boat. Note: After each boating outing, after the holding tank is pumped out, I fill the tank several times with fresh water at the pump out and then do a final pump. For winter lay up in my shed I removed the deck plug and leave the deck fitting open.

[fritzman]

I have changed all hoses and tank, yes it is a big project, but my boat is 25 years old when I did that, pictures included.

[fritzman]

[fritzman]

Pictures is of old hoses, the new ones where white and yes I changed the pump too. Once your in there change every thing since it is a sh--ty job.

[watchthis]

Is the stink in your bathroom or outside the boat? If its outside your boat, that is a completely different issue and it may be solved by using Odorlos or NoFlex and increasing the vent size to 1". If the smell is in your head (bathroom, not imaginary) and you boat in salt water, it is generally caused by dead and decaying tiny sea organisms coming in through your raw water flush and there isn't much to about that. It goes away after a couple of flushes. I chased this problem a few years ago. It wasn't the tank or hoses. I have a brand new filter in the box I will send you for the cost of shipping. I will never use it.

[coyote848]

The stink is pretty bad outside. I haven't explored to even see the tank or hoses because under the platform there is a piece of soundproofing or insulation so the tank and hoses are not exposed. I live in Maine and waiting for the weather to break so warm enough under the boat covering to begin these projects that one finds when purchasing a used boat. I don't have a clue where the tank vents out the side of the hull but assuming below the bathroom area.

[coyote848]

Is this filter the big orange filter that has been mentioned? If so I would be glad to take it off your hands.

[watchthis]

Nope, its another highly rated filter made here in the US called AirForce model #DR001

[Pcpete]

Watchthis is spot on if you are in salt water. On my previous boat I replaced the flush water hose annually. On our current boat, the first order of business was to rare place the black water hoses (and remove two grocery bags full of air fresheners) then change the toilets to electric freshwater flush. After that I added a second one inch vent line and made the 5/8” line so it goes strictly uphill, no chance of trapping water. End of problem.

[Spyderweb2]

Always had this problem in my boats, and it was from holding tank vent. Tried all kind of chemicals, with No flex being the best, but odor was still there. When I bought current boat, it already had a big orange filter installed. No odor since. My son-in-law bought my 285, installed a big orange filter, and he’s been odorless since.

[coyote848]

what is this big orange filter and where can I get one? thanks

[Centerline2]

holding tank odors can be eliminated by adding another vent to the tank so that there can be some positive ventilation, rather than just the single existing tube that keeps any pressure in the tank from building....

oxygen gets used up quickly in the holding tank, and if you can create a way to get more oxygen in there, the good bacteria (which doesnt have a strong offensive odor) can thrive.... its the anaerobic bacteria that thrive in the absence of oxygen, that creates the severe foul smell that is so annoying...

im not one to advocate for the use of chemicals in a marine holding tank, but as an RV'er, I can say that the best chemical one can get short of using the good old fashioned formaldehyde type tank deodorant (which is bad because it kills ALL the bacteria in the holding tank, and other organisms wherever the tank is dumped) is to use BORAX..... the actual process of the borax in controlling tank odor hasnt been studied, but its believed that as the boarax breaks down in the effluent, it creates/releases oxygen into the effluent, which helps the good bacteria survive.... but regardless of the science, in an RV, if you flush your tanks well, and then start using borax in place of any other holding tank chemical, the tanks will never have a strong odor until the borax is consumed, which then only needs a couple more tablespoons of borax to kill the odor again... usually 1/2 to 1 whole cup is used to charge a 40gallon holding tank, and will last about 2 weeks in hot weather... and BORAX is not damaging to the sanitation system in the RV, or on shore, so there are no environmental concerns to wonder about....

what you do, or how you do it on your boat isnt my business, but I do agree that one shouldn't have to live with a holding tank stink...