How does Austin’s hard water affect my pool’s calcium levels?

“In Austin, your pool is constantly trying to turn into a limestone cave.”

Central Texas has some of the hardest water in the country. This means it’s packed with dissolved minerals, primarily calcium. For a pool owner, this creates a one-way street: your calcium levels will only ever go up.

The Evaporation Cycle

When water evaporates from your pool, it leaves all the minerals behind. When you refill the pool with Austin tap water, you’re adding even more minerals. Over a few years, your Calcium Hardness can climb from a healthy 200 ppm to a dangerous 800+ ppm.

Expert Management Tips:

1. Partial Drains: Once your calcium hits 600 ppm, it becomes very difficult to balance. The only way to lower it is to drain a portion of the water and refill.
2. Avoid Calcium-Based Chlorine: Many “shock” products (like Cal-Hypo) add calcium to the pool. In Austin, we recommend using liquid chlorine (Sodium Hypochlorite) instead to avoid adding to the problem.
3. Monitor pH: High calcium isn’t a problem until the pH rises. Keep your pH at 7.2-7.4 to prevent that calcium from “falling out” of the water and onto your tiles.

Austin Detail: The “White Crust” you see on stone waterfalls in West Lake and Cedar Park is the direct result of this hard water cycle.

Sent from my iPhone while checking a waterfall in Northwest Hills.