We have issues with calcium, rust and lime. We also choose not to flush our toilet with every use in an effort to reduce our water consumption. This means the build up in our toilets happens quick and can be nasty. I have tried other brands that specifically target calcium, rust and lime. Some work, some do not. None of them worked as well as this Lysol did. This product is excellent. It works fast and well. It melted the rust and lime right off the toilet bowl so I had very little scrubbing to do. It helps control odor as well. It works great and at less than half the cost of other brands.