During our first camp with this new TT, I added the chemicals from the dealer when we arrived at the campground. We had no odor issues. I dumped and thoroughly backflushed before we left the campground. I did not add anything to the tank afterwards.However, on our second trip, I did just as before and added the black tank chemical right when we arrived. On day 2 we noticed an odor when we flushed and the flap was open. It got worse and worse each day. We made sure we used plenty of water when flushing. The black tank dump valves were closed the whole time. We cleaned the toilet bowl thoroughly to make sure that wasn't the problem. The flapper holds water just fine. The smell only occurs when flushing. The only other variable I can think of that was different between the two trips is on trip #1 we left the gray and black dump valves closed the whole time, then dumped each at the end of the trip, but on trip #2, I left the gray dump valve open (and black valve closed) til the next to last day so it could fill and be used to rinse my dump hose after I dumped the black tank.Any thoughts/advice are welcome.

Are you using a clean-out wand similar to THIS ONE each time the tank is emptied ?

Are you adding water when you put in the chemicals? About 5 gallons?

GMandJM wrote:Are you adding water when you put in the chemicals? About 5 gallons?Having a tank with an unknown history.......I never leave my tank completely empty for very long and add about 1/4 cup of bleach to ~3-5 gallons of water before driving to it's storage location.....so it can slosh around on the way there.P.S. Where was that grey water going during the time you had that valve open ??

I would guess that either your toilet, tank and vent design allows the gasses to permeate up through the toilet, or the tank vent is not venting. Is the air flow in the bathroom such that it would want to pull air from the toilet?

GMandJM wrote:Are you adding water when you put in the chemicals? About 5 gallons?No, I did not. I simply put the blue packet in with the very first flush of the trip. :S

foul odor when flushing | Good Sam Community

Rick57
Explorer
Aug 04, 2015
Wishbone51 wrote:
Rick57 wrote:
If you keep your sewer valve open and not allow the waste to stay in the tank...

Isn't that the first no-no you learn when RVing?

Hello Wishbone51
Yes it is better to keep water in your tank then release before you leave or when it is full. Still have to rinse the tank with fresh water. Some use the shower head to refill the tank. I forget not every RV has a rotating rinse inlet like mine has. I guess the main thing I was trying to pass on is leaving 2 in of water in the bowl leaves a barrier to help hold the smell at bay.
Wishbone51
Explorer
Aug 03, 2015
Rick57 wrote:
If you keep your sewer valve open and not allow the waste to stay in the tank...

Isn't that the first no-no you learn when RVing?
rrbowman
Explorer
Aug 03, 2015
texasAUtiger wrote:
During our first camp with this new TT, I added the chemicals from the dealer when we arrived at the campground. We had no odor issues. I dumped and thoroughly backflushed before we left the campground. I did not add anything to the tank afterwards.

However, on our second trip, I did just as before and added the black tank chemical right when we arrived. On day 2 we noticed an odor when we flushed and the flap was open. It got worse and worse each day. We made sure we used plenty of water when flushing. The black tank dump valves were closed the whole time. We cleaned the toilet bowl thoroughly to make sure that wasn't the problem. The flapper holds water just fine. The smell only occurs when flushing.

The only other variable I can think of that was different between the two trips is on trip #1 we left the gray and black dump valves closed the whole time, then dumped each at the end of the trip, but on trip #2, I left the gray dump valve open (and black valve closed) til the next to last day so it could fill and be used to rinse my dump hose after I dumped the black tank.

Any thoughts/advice are welcome.

I would guess on the second trip you had the bathroom fan on when flushing the toilet. That will pull odors from the black tank into the B/R. If that was the case either shut fan off when using the toilet or only turn fan on when showering, that's when it is beneficial.
Rick57
Explorer
Aug 03, 2015
Hello texasAUtiger
Bare with me there are several points. If you are parked and hooked up to sewer there are two ways to keep the smell at bay. If you keep your sewer valve open and not allow the waste to stay in the tank the trick is to flush and then fill the bowl with about 2 inches of water this makes a seal so the smell stays in the tank. If you do it this way fill your tank and then dump into the sewer before you leave. That way you can rinse the solids from your tank and save on chemicals.

If you are hooked up to sewer and keep your tank valve closed and wait to dump you will need to use chemicals. Still leave the tow inches of water in your bowl in any case.
Ron3rd
Explorer III
Jul 22, 2015
texasAUtiger wrote:
GMandJM wrote:
Are you adding water when you put in the chemicals? About 5 gallons?

No, I did not. I simply put the blue packet in with the very first flush of the trip. :S

That's likely your problem, always fill the black tank with a few gallons of water after you dump. Don't dump until nearly full if possible. Also, don't leave the dump valve open when connected to sewer, lest you want to experience the poop pyramid.
stugpanzer
Explorer
Jul 22, 2015
If you have any vent fans on, you might pull odors from the black tank when flushing. Our toilet procedure is, use pot, flush, then vent with roof vent fan if needed in that order!
2gypsies1
Explorer III
Jul 21, 2015
Wouldn't it be nice if the holding tanks were clear glass and we could all see inside them to know what's going on? :)
Vulcan_Rider
Explorer
Jul 21, 2015
1775 wrote:
Forget the packets - buy the chemical in liquid and there are measurements on the side of the bottle. The packets are supposed to dissolve - but they don't always.

Really ? I'm having some strange images trying to imagine how you KNOW that for sure.

To each his own.

I have no problem with the packets and am pretty sure that they dissolve just fine, as evidenced by the flowery smell I get shortly after putting it in.
1775
Explorer
Jul 21, 2015
Forget the packets - buy the chemical in liquid and there are measurements on the side of the bottle. The packets are supposed to dissolve - but they don't always. And after every time you dump the black tank you should be putting water in the amount of 10% of the tanks capacity right down the toilet immediately after dumping - along with the chemical. If the tank holds 40 gallons put four gallons of water in. Always keep your tank with water in it and you will avoid problems. In the winter if you winterize instead of water put the same amount of RV antifreeze into the black tank for the winter.

If you do all of this the only time you should begin to get a odor when the flap is open is when the tank is almost full. If it is really hot outside use more chemical if you start to notice an odor sooner.
2oldman
Explorer II
Jul 17, 2015
Vulcan Rider wrote:
how difficult can it BE to open the valve for about 15 seconds ??? I mean REALLY. :R
I agree. Better to do that than allow gunk to accumulate.