A pH corrector or neutraliser corrects the pH of the water to a neutral pH (7.0).
This in-line system is available in a range of sizes to suit various applications.
Low pH water is acidic and aggressive towards metal plumbings and fittings. This aggression can dissolve metals such as iron, cooper and zinc into the water, causing staining on fittings and fixtures and often being quite metallic in taste. 
These issues can be corrected by neutralising the acidic water using inline filtration though Calcite Media (calcium carbonate).
 
Model 171: For filtration to storage
Model 884: For homes
Model 1054: Light commercial applications