Ferrous Iron And Compensated Hardness - A.O. Smith AO-WH-SOFT-350C Owner's Manual

Ferrous Iron
NOTICE: If the water supply contains ferrous iron, a commercially available resin bed cleaner should be used
every six months. Follow the instructions on the container. You should increase your water hardness setting by
5 grains per gallon (86 mg/L) for every 1 ppm (1mg/L) of ferrous iron.
Ferrous Iron
(a/k/a clear water or dissolved iron)
Ferric Iron
Organic Iron or Bacterial Iron
Colloidal Iron
Determine Your Compensated Hardness
Compensated Hardness is the amount of
ferrous iron present in the water as well
as hardness content.
To determine compensated hardness
in standard measurements you should
increase your water hardness setting
by 5 grains per gallon (86 mg/L) for
every 1 ppm (1mg/L) of ferrous iron.
Use the section below for guidance and
fill in the blank chart below to determine
your Compensated Hardness.
DESCRIPTION
Actual Hardness
(use your test results
for hardness)
Ferrous Iron
(x5 for standard)
or (x86 for metric)
Compensated Hardness
(add first two results for
final result)

FERROUS IRON AND COMPENSATED HARDNESS

IRON
RESULTS
+
=
DESCRIPTION
Only type of iron that can
be treated with a water softener.
Insoluble and the particles can eventually
foul a resin bed. It should be filtered out
before the water reaches the softener.
Attached to other organic compounds in
the water. Additional treatment is needed
to remove this type of iron.
Not dissolved, yet stays in suspension.
A softener cannot remove this type of iron.
Standard Example
This example uses 3 (ppm or mg/L)
of ferrous iron present in the water.
DESCRIPTION
Actual Hardness
Ferrous Iron
*
times five (x5)
Compensated Hardness
(20+15)
* Add five times (x5) the iron content in ppm
or mg/L to the actual hardness
Metric Example
This example uses 3 (ppm or mg/L)
of ferrous iron present in the water.
DESCRIPTION
Actual Hardness
Ferrous Iron
*
times eighty-six (x86)
Compensated Hardness
(342+258)
* Add eighty-six times (x86) the iron content
in ppm or mg/L to the actual hardness
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7
RESULTS
20 gpg
15
35
RESULTS
342 mg/L
258
600