I have used Blue Streak for years. It costs a bit upfront, but is worth it. It dispenses a bit of chemical with every flush. That eliminates the guessing about how much to add based on how long you will be camping, eliminates forgetting, eliminates the mess. Since some stays in the bowl, it helps keep things clean and the seal good. There is a faint baby powder scent, but not strong. I will be installing one in my new RV we just bought. Look into it, especially those of you who use the rig a lot.