Calculate your hardness:

Either in PPM (Parts Per Million) or in GPG (Grains Per Gallon)
• If you have PPM convert by dividing by 17.1
• If you have GPG convert by multiplying by 17.1
Until you have reached your grain hardness

First Determine if a softener is needed, see defined chart below.

Terms Defined

Soft1.0 or less17.0 or less
Slightly Hard1.0 to 3.517.1 to 60
Moderately Hard3.5 to 7.060 to 120
Hard7.0 to 10.5120 to 180
Very Hard10.5 or over180 or over

* GPG -Grains Per Gallon

**PPM – Parts Per Million

Compensated hardness:
When sizing water-conditioning equipment, the hardness should be based on compensated hardness. Compensated hardness takes into consideration minerals and other factors that will reduce the softening capacity of a softener. These items cannot be picked up in a standard hardness test. To arrive at compensated hardness,
multiply the figure on the right by the hardness in grains per gallon.

Note: Always Determine both (1) FLOW RATE and (2) CAPACITY total in grains

Your Test HardnessYour NumberMultiply ByYour Number=Compensated Hardness
1 -201.1
21 – 401.2
41 – 701.3
71 – 1001.4
101 – Plus1.5

Flow Rates in Pipes

3/4″=10-15 GPM
1″=16-30 GPM
1-1/4″=30-35 GPM
1-1/2″=40-70 GPM
2″=65-120 GPM
2-1/2″=80-170 GPM
3″=120-270 GPM
4″=250-500 GPM
6″=500-1100 GPM
8″=1000-2000 GPM
10″=1500-3000 GPM

Number of People using softened water in household

Number of people using softened water in household