All About Treating An Acidic pH
The pH scale goes from 0 to 14 (7 is neutral). 0 is the
most acidic and 14 the most alkaline. In most homes the desirable range is 7.0-8.0. The State recommended range
is 6.4 - 8.5 (note: a pH of 6.4 is 6 times more acidic than neutral!). Many factors influence the corrosivity of
water including total alkalinity, hardness, dissolved oxygen, carbon dioxide, TDS (total dissolved solids) and
temperature. In many ways the best indicator of a corrosion problem is the blue/ green staining caused by the leaching
of copper pipes (copper oxide) most commonly seen in the bathtub.
There are two common treatment methods:
1. Neutralizing filters bedded with calcite (CaCo3) and corosex (MgO)
2. Chemical injection systems using either sodium or potassium carbonate
NEUTRALIZING FILTERS:
Are available in automatic and manually backwashed down-flow units & non-discharge up-flow models. They are
named for the water's flow path in the service (treatment) cycle.
The down-flow method provides filtration because the water passes through a packed bed of filter sand.
The up-flow method diffuses the water more effectively, creates improved contact time and allows for a greater
ratio of corosex to calcite and so can handle more acidic pH.
Both feature minimal homeowner involvement and usually only require yearly servicing. They're ffective from a pH
of 5.8 with a down-flow water path and from 5.0 with an up-flow water path. In both cases the pH will be corrected
to between 6.8 - 7.5. One disadvantage is that approximately 50.0 ppm of calcium (hardness) is added as a by-product
of treatment.
SODA ASH INJECTION SYSTEMS:
Feed a metered amount of alkaline solution (usually soda ash or potassium carbonate) into the water, commonly just
ahead of the water storage tank. Typically, the metering pump is wired into the water pressure switch to operate
simultaneously with the well pump. Usually, a static mixer or contact tank is used to insure a more complete reaction
with the treatment solution. The homeowner visually monitors the level of treatment solution and mixes up more
as required (a simple and quick process done every 2-4 months).
An injection system can handle more acidic pH levels and raise the pH higher if needed. It adds no hardness to
the water but does add approximately 30 - 50 ppm of sodium or potassium to the water. It offers no filtration and
doesn't restrict water flow. Another advantage is that it allows you to correct the acidity problem ahead of the
water storage tank.
Which method is best? It honestly depends on the specific water chemistry, type of well pump and the homeowner's
lifestyle. As always, please feel free to call with any questions!