Monday, June 8, 2015

How Copper Corrosion Causes Blue Staining and What to Do About It

Dear sir,

Our water permanently stained our sinks, tubs and fixtures a blueish green color.  The water also has a bitter taste  What causes this and how can we filter it out?  We have well water.   I have attached a copy of our water test.  We already have a water softener in place.

Edward S.

Dear Edward,

Your water test report shows your well water has a pH of 5.8.   This is called 'low pH' or 'acid well water'.   The water looks good otherwise.  The water is not very hard, nor does it have iron or manganese in it.    The acid water dissolves your copper piping.  Copper turns blue when its oxidized, and will also impart a very bitter taste to the water.

 Treatment is accomplished by neutralizing the water with the use of an automatic calcite neutralizer. These water filter tanks are filled with a blend of calcium and magnesium carbonates made from naturally occurring minerals, which dissolve into the water, making it less corrosive.

Calcite is a white granular mineral that adds calcium to the water raising the pH and increasing the alkalinity.  Periodically, (once or twice a year for a typical residential application) more mineral is added to the filter tank.  These filters will typically raise the pH of the water to 7.0 to 8.0 and add 30 to 100 ppm of hardness depending on the alkalinity and water hardness.

In neutralizer filters, acidic waters slowly dissolve the calcium and magnesium media on contact as the water flows through the filter, raising the pH of the water and increasing the alkalinity. This eliminates the effects of corrosive water chemistries and can help to prevent corrosion of piping and fixtures.

See the diagram below, you would want the neutralizer to be installed before the water softener. 

For more information about this acid neutralizer, you can check out this link.