If you’ve ever noticed a white, chalky buildup on your pool tiles that won’t scrub off, or only comes off with difficulty, that’s calcium scale. While proper chemistry can help prevent it, if the water is loaded with minerals—particularly calcium—it can become inevitable over time, especially in places like Arizona where the water is very hard.
There are ways to chemically or manually remove scale, but they are extremely labor-intensive and only moderately effective. At a certain point, abrasion using a blast media (also called tile blasting) is the best option.
All water naturally contains minerals—this is commonly referred to as "hardness." If you’ve ever left a glass of water out and noticed a chalky residue left behind when it evaporated, those are minerals that were dissolved in the water. The same process happens to pool tile.
Over time, as water evaporates, calcium hardness builds because calcium itself does not evaporate. Pools can lose 30% of their water each year to evaporation, meaning calcium levels can increase by the same percentage annually. Eventually, this calcium, which was once dissolved in the water, precipitates out and clings to the pool surface. Since this process happens as water evaporates, scale is most visible at the waterline. If you have water features or an overspill spa, it can also be very noticeable in those areas.
In the long run, because water evaporates and mineral concentrations build, yes, scale formation on your tile is inevitable unless you drain the water periodically. However, there are ways to slow it down and keep it at bay for years.
The first is proper chemistry balance, though it can get complicated. For more on the exact science, check out the Langelier Saturation Index. In short, keeping pH, alkalinity, total dissolved solids (TDS), and calcium hardness properly balanced goes a long way in preventing scale.
Keeping your chemicals balanced helps, but in places with very hard water like Arizona, the only way to definitively prevent scale formation in the long term is regular draining.
There are a few ways to tackle calcium deposits, and each method has pros and cons:
There are different types of blasting media, but we use kieserite, a natural mineral composed of magnesium sulfate (Epsom salt). Kieserite is softer than ceramic tile but harder than calcium scale, making it effective at removing buildup without damaging the tile surface.
Some companies use glass beads, which can work well, but they are harder than kieserite. While glass beads can remove scale more quickly, they also carry a higher risk of etching or damaging the surface, especially softer surfaces like stone.
The short answer is no, tile blasting can be done without draining the pool. However, the tile formed scale for a reason, and that reason was the chemistry of the water, which means the risk of scale reforming is high if the water is not turned over.
That’s why we strongly recommend draining and refilling as part of any tile blasting service. This ensures the longevity of the cleaned tile and helps reset your water chemistry. We can test your water to check its scale-forming potential, but in most cases, draining is the best long-term solution—unless the pool was recently refilled and the scale buildup is from older water.
Once blasting is complete, we begin refilling with fresh tap water and return once the pool is full to rebalance the chemicals and restart the filtration system.
Calcium scale happens to almost every pool at some point—especially in areas with hard water like Arizona. Tile blasting is one of the most effective ways to restore a clean, polished look. It’s a straightforward process, and when done right, it keeps your pool looking great without damaging the tile. If you ever have questions about what’s best for your pool, we’re always happy to chat—no sales pitch, just straight answers.
