I have used toilet tablets but still got smells even after flushing the tanks really well once home and on a good water supply.
I started adding a cup of bleach and some dawn dish detergent to a 6 gallon bucket then mixed it into a foam using a paint stir plastic fan thingy in my cordless drill. it makes a great thick foam. That goes into the toilet and each sink drain and shower. During my trips i spritz the commode after each use with a cleaner containing bleach and i haven't had any odors nor do I use the tablets anymore.
i read about the Geo method and will be adding the water softener next time. The tablets produced an odor that i didn't care for.
I happen to be a person who detects odors that others can't smell. My neighbor found that useful when he had a dead rat in his garage and couldn't find it,I walked right up to it's resting place behind his work bench. TMI ? ....maybe.....