The build up on this pool tile is from a crack in the spa wall. When you see Calcium pouring out of the grout lines in your pool tile, that Calcium is coming from the wall behind the tile, not from the water chemistry of your pool water. pH of concrete is around 13, pH in pool water should be 7.4. So when you run 7.4 pH water through 13 pH concrete, it is drawing the Calcium out of the concrete because of the large gap in pH. This water can't push through the solid tile, so it finds it's way to a grout line and passes through.
If you don't maintain your pool water, the pH will climb to about 8.0 pH, that's where it will go if you don't add acid. SO, when water that is not maintained properly flows through concrete, it will pull less Calcium, which means, the areas that are pouring out of the grout lines will be much less. But, that 8.0pH water will leave a ring around your pool, and white shadows around and under your spillways.
The lesson here is, you get Calcium build up from two processes. Poor water chemistry, which shows up as the bath tub ring and shadows under the spillways, and, or, water flowing through a crack in the concrete shell, which shows up as dripping out of the grout lines.
San Diego Pool Tile Cleaning can clean the build up from both! We can provide an online estimate with a little info and a couple of pictures, or you can give us a call 760-721-3037
