|Hardness in GPG||1 to 2 People||3 to 4 People||5 to 6 People||7 or More|
|1-10 GPG||32,000 Grain||32,000 Grain||48,000 Grain||48,000 Grain|
|11-20 GPG||32,000 Grain||48,000 Grain||48,000 Grain||48,000 Grain|
|21-30 GPG||48,000 Grain||48,000 Grain||64,000 Grain||80,000 Grain|
|31-40 GPG||48,000 Grain||64,000 Grain||64,000 Grain||80,000 Grain|
|41-50 GPG||64,000 Grain||64,000 Grain||80,000 Grain||80,000 Grain|
Ideal regeneration frequency is 10 to 14 days at 75% of total capacity. Why 75% capacity? 25% reserve capacity is necessary in case of excessive water use from time to time. Example: 3 people (75 gallons per person per day) in a home avg. 225 gallons of water used per day with 15GPG will need a 32,000 grain system set up for 24,000 grain capacity.
Converting PPM to GPG
If you need to convert hardness from ppm to Grains per gallon (GPG) divide the total water hardness by 17.1. Example: 200ppm of total hardness / 17.1 = 11.69 GPG
Adjust for Iron
If iron is present in your water supply please add 5 grains of hardness for every 1 ppm of iron and determine your size water softener from there.