Floyd recommended Odolos to me and it is great. My wife and I can't deal with any of the scented stuff. Odorlos is not sold everywhere it is sold at CW, West Marine (high cost) and Amazon. It comes in liquid, powder and powder packs. Don't put your chemicals in first thing, they will settle in the end of your dump tube. It's best to have the bottom of the tank covered in fluid. I use mostly powder in the toilet but add a little liquid to the kitchen sink drain.

Eddie