Depending on its size, the amount of resin should be anywhere from 0.64 to 2.00 cubic feet. When you get the amount right, you eliminate one potential source of water softener problem.

How do I calculate softener resin?

Use the following formula to calculate the proper size: Multiply the number of people in your family times 70 (gallons of water used per day, national average). Multiply the answer by your water hardness in grains per gallon (to convert mg/l or ppm to grains, divide by 17.1).

How many cubic feet of resin is in a water softener?

What is sold typically as a 32,000 grain system contains 1 cubic foot of water softening resin. If one looks at the specification provided by the resin manufacturer you will see that 1 cubic foot of resin under ideal laboratory conditions can remove about 32,000 grains of hardness.