The terms hard and soft when referring to water might seem a little confusing at first. Water is water, after all, isn’t it? Actually, it isn’t. When we talk about hard water, we’re referring to the amount of calcium in the water. The ideal range for swimming pools is between 180 and 220 parts per million (ppm). In hard water areas, the levels of calcium are over 400ppm. This is when managing your water chemistry becomes a little bit trickier. It’s important to balance out the hardness of your pool water, as hard water can actually damage your pool and leave an unsightly white residue on ladders, pool decks or tiles, and other surfaces. This is called scaling and is caused by the calcium drying and hardening on a surface.
If, however, you live in a hard water area, there’s no need to panic! Many pools operate very happily in the 400-800ppm range. You just have to take extra care to keep your pH and alkalinity under control, and use a stain and scale chemical to help keep your water clear, and prevent any build-up of scale.
Treating A Hard Water Pool
Maintaining low alkalinity and pH levels in your pool is the most important aspect of looking after a hard water pool. This is especially critical in the summer when the water temperature increases. Keeping the pH at about 7.2, and the alkalinity below 100ppm means your pool is less likely to produce scale, or become cloudy.
It’s also important to use chelators or sequestrants, which are stain and scale chemicals. They help to bind minerals and metals in the water, keeping them dissolved and therefore preventing staining or scaling. Remember that these chemicals do deplete rapidly, so maintenance doses should be added to your pool once a week, after the initial first dose at the beginning of Spring.
If you’ve previously been shocking your pool with a calcium hypochlorite pool shock, you might want to discontinue doing so if you have a hard water pool. It simply adds more calcium to your water, which is something you ideally want to avoid.
If you have any questions about pool maintenance, or would like professional assistance with all things pool- or water feature related, talk to the friendly experts at Pool, Spa and Filtration Supplies. We have over 30 years of experience, and are great are finding solutions to any problems you might have with your domestic or commercial swimming pool, fish ponds, aquarium Jacuzzis or spa.