Bests & Worsts Reviews from Amazon

I am writing a review of three toilet cleaning systems I've bought here on amazon: Fluidmaster: Uses a cartridge containing a chlorine based tablet. Cartridge is not meant to be refilled. Chlorine odor noticeable in the bathroom. Cartridge can be modified (I used a dremel) so it is easily refilled. NeverScrub: Uses a cartridge containing a chlorine based crystal. Cartridge is not meant to be refilled. Chlorine odor noticeable in the bathroom. Kaboom: Does not use a cartridge. Bromine tablet refill inserts directly by unscrewing a cap. No odor noticeable in the bathroom. All three of these systems work the same way and all are really easy to install. All of them put a toilet cleaning chemical (tablets or crystals) in-line between the water fill valve and the toilet bowl fill pipe. All of them prevent the chemical from getting into the tank water (so there is no damage to the plastic parts in the tank). All sell refills for their systems. All keep the toilet bowl equally clean for about 1-3 months depending on how often it is flushed. Amazon also sells Pool/Spa Cleaning Chlorine and Bromine tablets, which as far as I can tell do just as good a job keeping the toilets clean as the refills but at a fraction of the cost. I have tried all of the following, each of which provide enough tablets to keep all the toilets in the house clean for 10 years and they are all very cheap: Kem-Tek 177: The tablets fit well in the dremel-tool modified Fluidmaster cartridges. The tablets fit well in the Kaboom. The bathroom has a slight chlorine odor. Spa-Kem 267: The tablets are too large to fit in the Fluidmaster cartridges. The tablets fit well in the Kaboom. No odor. Tropi Clear: The tablets fit well in the dremel-tool modified Fluidmaster cartridges. The tablets fit well in the Kaboom. No odor. Chlorine and Bromine are fairly equal in cleaning ability. Chlorine has that chlorine odor. Bromine is broken down by sunlight. Which is why, on a sunny day, outdoor pools use chlorine. But at night, or indoors, or on a cloudy day, they use bromine since there is no smell. Summary. The Fluidmaster system works but the cartridges are expensive. To refill the cartridges easily requires a small modification with a dremel tool. The cartridge is too small for any tablets larger than 1 inch in diameter. The NeverScrub system also works but the cartridges are expensive. What I am using is the Kaboom system with the bromine tablets (either the Tropi Clear or the Spa-Kem 267) as they have no odor and clean just as well as the chlorine tablets.