Home
Back
GPG Formula:
| From: | To: |
Grains per gallon (GPG) is a unit of water hardness measurement. One grain per gallon is equivalent to 17.118 parts per million (PPM) of calcium carbonate dissolved in water. It's commonly used in water treatment and softening applications.
The calculator uses the GPG formula:
Where:
Explanation: The formula converts the concentration of dissolved minerals from parts per million to grains per gallon, which is a standard measurement for water hardness.
Details: Measuring water hardness is crucial for determining appropriate water treatment methods, preventing scale buildup in pipes and appliances, and ensuring optimal performance of water-using equipment.
Tips: Enter the PPM value of your water sample. The value must be greater than 0. The calculator will automatically convert it to grains per gallon.
Q1: What is considered hard water in GPG?
A: Generally, water with 1-3.5 GPG is slightly hard, 3.5-7 GPG is moderately hard, 7-10.5 GPG is hard, and above 10.5 GPG is very hard.
Q2: Why is GPG used instead of PPM for water hardness?
A: GPG is the traditional unit used in water softening industry, particularly in the United States, and is the standard measurement for sizing water softeners.
Q3: How often should I test my water hardness?
A: It's recommended to test water hardness annually, or whenever you notice changes in water quality, after moving to a new location, or before purchasing a water softener.
Q4: Can I use this calculator for any dissolved minerals?
A: This calculator specifically converts calcium carbonate equivalent. For other minerals, different conversion factors may be needed.
Q5: Where can I get my water tested for hardness?
A: Water hardness test kits are available at hardware stores, or you can contact your local water utility or a certified water testing laboratory.