Rather than buy nasty and expensive chemicals for the waste tanks try using a 1/2 cup of good old Borax laundry detergent and 1/4 cup of water softener. The Borax detergent helps control odor and cleans the tank. The water softener makes the water softer and more slippery, preventing waste from sticking to the walls of the waste tank.
I’ve been using this combo while living and traveling full-time our RV for the last four years with good results. Rarely do I have an odor problem and never had a tank plug up. The trick is to use plenty of water when flushing and only dump the tank when it is nearly full.
Boondocking Waste Tank Cleaner
When off the grid boondocking with our RV we have to be much more conscious of our water use and conserve as much as we can. In this instance and if the weather is hot the Borax solution may not be enough to prevent odors.
For dry camping like that, I recommend a product called “Happy Camper“. I really like it because it doesn’t have that noxious perfume smell so many tank deodorants have. It actually has no smell whatsoever but works great! It also works well at completely liquefying the toilet paper preventing clogged pipes.
For some more black tank tips and tricks check out my forum post on theLove Your RV Forum. Also Love Your RV has a huge and growing archive of RV Tips and Tricks posts.