If you’re seeing white crystals on your pool wall or in your cleaner, it’s calcium carbonate. Your pH spiked during the winter. When your water becomes very basic, it can’t hold as many minerals in solution and begins to shed them. In most pools the mineral that is in the highest concentrations is dissolved calcium so it’s the first to be shed. It crystallizes on your walls as carbonate. Very often, just adjusting your pH to the low side of ideal 7.0-7.2 will redissolve the mineral w/o any problems. If however the problem persists you may have to brush daily and lower your pH to 6.6-6.8 briefly, to break the bond that can develop between the pool wall and the crystal. Very rarely the bond is so strong that the pool must be emptied and the crystals ground off.
Next ArticleEvaporation and the Night Air