Certified Water Technologist Practice Exam 2025 – Complete Prep Guide

To determine how many gallons of water are softened per regeneration when using 10 pounds of salt per cubic foot, it's essential to understand how water softening and salt dosage interact. In this context, the amount of salt used directly correlates with the capacity of the softener to remove hardness from the water.

Typically, one cubic foot of standard water softening resin can effectively soften approximately 30,000 grains of hardness. The salt required for regeneration is necessary to recharge the resin, and the dosage of 10 pounds of salt per cubic foot is commonly used. In practice, each pound of salt will typically handle about 1,200 to 1,500 grains of hardness.

To calculate the volume of water softened during a regeneration cycle, you can use the following formula:

\[ \text{Gallons of water softened} = \frac{\text{Grains of hardness removed}}{\text{Grains per gallon of water}} \]

Assuming that the grains of hardness per gallon of water falls around 7.5 grains, if we use 10 pounds of salt, we can mobilize the ion exchange process, regenerating the resin for about 30,000 grains of hardness.

1 cubic foot of resin at 10