*Water Softener Sizing*

- Hardness Rating: expressed in grains of hardness per gallon
- The level of Iron: expressed in PPM (parts per million) or M/L (milligrams per liter)
- The level of Manganese: same expressions as per iron (PPM or M/L)

**Calculations:**

1. Calculate DEMAND -- Start by multiplying the population served times 80 (for general calculations, figure 80 gallons per day water usage per person). Example: a 4-person household would calculate to 320 gallons per day demand.

2. Add 2x the tested Iron level to the tested hardness
value. Example: Hardness level test results = 10.

IF that included 0.5 ppm iron. Add 1 grain (2 x 0.5 =
1) to the hardness value.

3. Add 2x the tested Manganese level to the tested hardness value. Example: Hardness level test results = 10. That included 1 ppm of manganese. Add 2 grains (2 x 1 = 2) of hardness value.

Summary example of steps 2 and 3 above: 10 + 1 (for the iron) + 2 (for the manganese) Calculated Equivalent Hardness Value = 13.4. Multiply DEMAND by the Calculated Equivalent Hardness Value. This will give you the GRAINS PER DAY figure. Example: 320 gallons times a Calculated Equivalent Hardness Value of 13 = 4,160 grains of hardness per day.

5. It is most economical to size your water softener so that it does not need to regenerate more often than once a week. So, multiply the calculated grains of hardness per day by 7. As per example above: 4,160 grains x 7 = 29,120 grains per week.

In the example above, the H2O-M2010 (30,000 grain) water softener would be the properly sized unit. Capable of accommodating 29,120 grains of hardness removal per regeneration.

NOTE: If your water tests over 1 ppm for Iron, you should consider iron removal pre-treatment technology. Contact ESD at 602-649-3050 or to discuss iron removal.

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