Final answer:
The white build up on shower heads and faucet aerators is primarily caused by the precipitation of minerals from hard water, particularly cations like calcium and iron. These deposits can be mitigated by using ion exchange resins or other builders in cleaning products, while oxygen-based bleaching agents can help break up organic deposits.
Step-by-step explanation:
The white build up on shower heads and faucet aerators is caused by the precipitation of minerals from hard water. This water contains excessive amounts of cations such as iron and calcium. These minerals come out of solution and form deposits on surfaces that they come into contact with, such as the inside of a shower head or faucet aerator.
Ion exchange resins are often used to remove these minerals and soften the water. Builders, also known as chelating or sequestering agents, are added to some cleaning products to act as water softeners. They work by removing hard water ions through different processes like precipitation, chelation, or ion exchange.
While phosphates can bind calcium and magnesium ions to prevent the deposits, their use has been diminished due to the ecological damage they can cause. Instead, oxygen-based bleaching agents may be used to break up and bleach these organic deposits without the harmful environmental impact.