What is that white and gray build-up at the water line of our pool tiles?
The short answer “hard” water deposits. The long answer is how the water gets “hard.” As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water “hard.” The degree of hardness becomes greater as the calcium and magnesium content increases. Many areas that have ground water run into the problem of “hard” water. Dissolved minerals from the “hard” water deposit on the pool tile at the point where the waters surface meets the atmosphere. As the water evaporates the minerals are left behind, over time they build-up leaving the white and gray build-up around the water line.
