My practice:
1. To maintain my blackwater holding tank I use two tablespoons of Happy Camper Odorless Holding Tank Treatment (53 cents) dissolved into two gallons of water dumped into an emptied blackwater tank.
2. Happy Camper is biodegradable, works in all temperatures, eliminates odor, dissolves toilet paper, liquifies waste, and keeps sensors working properly. I use any two-ply toilet paper that is safe for septic tanks.
3. Proliferation of anaerobic bacteria causes odor. Happy Camper promotes aerobic bacteria which crowds out or kills anaerobic bacteria and accelerates decomposition.
4. With Happy Camper there is no need to use excessive amounts of water. Just two gallons to start and normal use of the toilet and bathroom sink. Filling an empty black tank one-third full with water is wasteful.
5. Happy Camper is the one blackwater tank treatment I've found that does work. No colored chemicals, no detergent, no water softener, no bleach, no chemical tablets, and no excessive amounts of water.
6. If possible, I wait until my blackwater tank is at least half full before dumping.
7. It is easy and cheap to try Happy Camper to see if it does indeed work for you.