Another neutralization technique involves addition of sodium carbonate (NaCO 3 ), sometimes called soda ash, into the water system. This should be injected ahead of the pressure tank, and may be mixed with chlorine solution if chlorination is also used. Keep in mind that soda ash adds sodium to your water. To prevent corrosion by creating protective films on plumbing components, chemicals such as polyphosphates and silicates may be injected into the plumbing system. Non-corroding plumbing materials, such as plastic or polyvinyl chloride (PVC) may be used if old pipes must be replaced.