Black Tank Deodorant

If you have the vents open and flush the toilet... bad odors come UP from the tank into the RV. I turn the ceiling vent (in the bathroom) off before I flush. (and when I'm dumping the tanks I make sure that all the ceiling vents are not running.)

I have used a couple of cups of pine sol on very hot stretches. Pour a good amount into the tank through the toilet. I don't use it on a regular basis but for those couple of hot weeks in the summer it sure seemed to ease the odor problem.

Blackcell wrote:
. . . flushing with plenty of water is key to reducing odor.

True, but this isn't an option for the OP who is boondocking.

I use the Geo Method and also RV Digest-It. Any product with formaldehyde should be avoided as it kills the bacteria which in turn results in clogged sensors and gummed up holding tanks.

Agree, flushing with plenty of water is key to reducing odor.

I have used the blue stuff from Thetford for years with no problems.Pour in a couple ounces and a couple gallons of water and there you go. Someone gave me some citrus smelling stuff once and it did not do as well.

Anything with formaldehyde in it. Any bottle of blue with formaldehyde will work.

Use more water. There is NO black tank treatment that has any smell I'd want in my bathroom. Using insufficient water is the more likely cause of your odor problems. Another thing you can do to assure no odors is to NEVER NEVER NEVER leave the black tank dry whether in use or in storage. There is always solids left behind no matter how much you flush your tank when dumping and these will turn to stone, create clogs and odors. I would never leave my black tank with less than 5 gallons of water in it, even when in storage.
Good luck / Skip

Bleach -- at least a couple of quart bottles. You might also want to do the same with the gray tank.

Bromine tablets for a hot tub. Kills bacteria which increase odor. Try one tablet to start and add one or 2 more every day.

Hot weather...10 days not dumping...good luck.
All I can suggest is to change your diet....:)

Seriously..not much can be done..to me, the treatments make it smell like someone pooped in a pine tree.

Lots of water is the gold standard. Otherwise all of the treatments out there do pretty much the same thing....pick your fragrance - it will last for about a week. After that it's as you say, "odoriferous!"

I'm sure you will get many suggestions, but I like Odorless RV holding tank treatment. Used it for years without any problems.

Good Luck