Toilet nasty smell solution.

[Jfrano]

Have been get nasty smells after flushing the toilet, like many of us. Read the numerous post here. Started tearing apart the berth, thinking of putting in a filter etc. Emailed Andrew, his simple solution, remove the exterior waste cap and blow air or water down the through hull vent. Got my wet/dry vac placed exhaust house over vent . Air pushed through and gurgling in the toilet . Tried flushing .... no smells ...problem solved. Simple and quick!
Suggested to Andrew, a series of bullet FAQs like these would make our boating quality of life soooo much more enjoyable.

 

[fishheadbarandgrill]

Cool trick. You successfully removed the methane layer from the top of the black water. Unfortunately, the anaerobic bacteria will continue to produce methane unless the aerobic bacteria can dominate the tank environment. Our vent lines, like most boats, are not large enough in diameter to allow sufficient oxygen into the tank to allow the aerobic bacteria to dominate. It will be a nice experiment to see how long it takes for the tank to smell again. For us, it’s 2-3 days of use no matter what product we use to treat the tank.

 

[Severum88]

We started with Noflex as new owners of a 2016 C26. I cleared the black water tank and added three tablespoons to the new tank. We use one scoop on days we use the boat. We have had near zero smells and have dumped the tank three times thus far. This stuff ain’t cheap but works.

 

[scross]

In addition to the chemicals we have found double pumping to be very helpful. Pump out then flush 3-5 gallons of fresh water from the shower head down the toilet then pump out again. We double pump every time we will be gone from the boat for more than a couple of days.

 

[SJI Sailor]

+1 to both recommendations. Noflex and Odorlos both seem to work well (add more every couple of days as noted). And double (or triple) pump out when no one is waiting!

 

[Salmon Fisher]

We have used the product "Forget About It For Boats." My wife has a really keen nose and after using it in the tank, says there is smell whatsoever from the head or vent. Even pumping out, she says no odor present.
You can get it on Amazon. We bought a bottle at the boat show and said we'd try it and glad we did. Apparently it introduces aerobic bacteria and that is the key.
We use "Happy Campers Organic RV Treatment" in our travel trailer and I believe it also introduces organic and aerobic bacteria. Again, no odor from using that in our black tank.
Hope this helps.

 

[Toki]

I'm guessing there was a blockage in your vent line, probably at the tank fitting, and the air blew it out. That simple.

 

[oberrys]

The black tank through hull vent looks like one of the semi covered fuel vent through hulls - it looks too restrictive for venting the black tank. I’ve thought about replacing it with with an open type through hull vent.

 

[BB marine]

I just experienced the black tank vent plugged on my C26. It is a 3/4 " waste hose that is run with a lot of peaks and valleys. I started noticing a slight odor in the engine compartment after a hot day and operating the engine. I have two engine exhaust blowers running when the engine is running to cool and vent the compartment but I was still noticing a slight odor. I also noticed when opening the waste deck fitting for pump out there was a small amount of pressure as I loosened the cap and I could hear it releasing the pressure has I removed the cap. After the last pump out I did a fresh water flush with non potable water hose at the fuel dock. I did this three times until the flow indicator on the pump out valve showed clear water coming out. I then went to our slip and removed the vent hose from the thru hull vent fitting. I attached a female garden hose fitting with a 3/4" barb fitting to the vent hose and attached my wash down hose to it. I tuned the wash down pump on and the pump stated running and stopped. The indication was the vent hose was plugged. I turned the pump off and released the pressure and repeated this 3 times and all at once the blockage broke free and the pump continued to pump. I let it run about 5 gallons of water through ( I'm in fresh water) to clean the vent hose of any junk that may have settled in one of the valleys. I then opened the deck hatches and lifted any of the low runs using cable ties. Hopefully this will help with the venting of the tank. I do not use raw water flush I installed fresh water flush just after purchasing the boat. I believe this helps keep some of the odors down. I use Odorlos at twice the recommended amount flushing it in the toilet so it runs through the 1 1/2 waste hose to the tank. So far after 4.5 seasons of use we have no odor in the boats living space or cockpit when flushing. I just did the vent cleaning a week ago so it is to early to tell if all engine compartment odors are gone completely. The vent line is small and the vent hose run on my boat is long. I think it could use better venting. I open my deck cap a couple times a weekend just to help it vent off some of the gases. There doesn't seem to be to much odor when doing this so the vent is working some.

 

[timdelta]

Would a bubbler, like a fish tank thing, help? It would increase the O2 levels, not use much power and cheap to buy and replace.