A common culprit of toilet bowl stains is the mineral build-up that can be seen around the water line and under the rim. This is especially true when hard water, which is high in mineral content, is the type of water being supplied to the household. As the water evaporates, minerals such as whitish calcium or magnesium compounds and rust-colored iron compounds are left behind, coating the upper part of the bowl and eventually hardening into a scale. Even with soft water, molds can still form a dark coating in the bowl. With slicker types of ceramics, such deposits are lesser. But constant scratching by abrasive cleaners and aging can leave the surface more susceptible to mineral and mold buildup.
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Choosing the Best Toilet Bowl Cleaner
