All water quality varies from place to place. Whether you are using well water or using the municipal water system, there will be differences in the mineral content and additives to the water. Some places have much harder water than others. Hardness, when referring to water, indicates the amount of calcium in the water. The higher the level of calcium, the harder the water will be. Hard water isn’t dangerous, but it can cause some issues in your pool that will have to be addressed from time to time.
Hard water will, over time, deposit minerals like calcium on the surfaces of your pool, the components, etc. When left untreated, it will build up over time and can create patches of very hard to remove calcium which can be unsightly and could, with time, cause issues for some of the components in your pool. While you can’t do anything about the hardness of the main water supply you use (softening your water is not a good option for pool owners), there are several ways that you can easily remove any calcium scale or build-up that does occur.
It is, of course, easiest to catch this problem before it gets too bad. Calcium scale, also often called limescale, first appears like white foam on the surface of the water. Over time, it will adhere to the surface of the pool, build up, and it can be quite difficult to remove it. Calcium scale can also lead to the erosion of pool surfaces as well.
The thing is, if there is calcium scale build-up on the visible surfaces and components of your pool, there is also likely build up in some of the inner workings of the pool too, such as the filter or lines. Build up in these areas can cause cracking, lines to break, clogs, and other serious issues.
Types of Calcium Scale
It might seem like calcium is calcium, but there are several different kinds of calcium scale you may deal with. Calcium carbonate and calcium silicate are the two main types of calcium scale pool owners are likely to encounter. Calcium carbonate is the most common type of calcium scale encountered. This is usually the result of high pH levels in the pool water. Research has shown that high pH helps to accelerate the development of calcium carbonate.
Calcium silicate is a little less common, but also a source of calcium scale in pools. Like calcium carbonate, this type of calcium scale is most likely to form when the pH is too high.
What Causes Calcium Scale?
As we mentioned earlier, one of the biggest culprits behind calcium scale is water hardness. However, high pH and alkalinity levels are also contributors to the development of calcium scale. If you know you have hard water, it is really important to do regular water checks to determine the level of calcium hardness in the pool, that way you can address it before it becomes a problem. If the hardness level is too high, chances are the alkalinity and pH are out of balance as well, which will exacerbate the problem.
Removing Calcium Scale
If possible, it is best to prevent calcium scale from getting out of control. We will touch on prevention in the next section. But if you already have a calcium scale, you will need to know how to address it. The most common means of removing calcium scale is to use muriatic acid on it. Chances are, you already have some of this around for pool chemistry management. Since this is a harsh chemical, you will want to make sure to take plenty of safety precautions when using it. If the buildup isn’t too excessive, vinegar and a brush may work well enough too.
You will want to lower your water level to be able to get at the calcium scale. Wearing gloves, you will use a spray bottle to spray vinegar on the scale. We love this extra strength vinegar because it’s very strong and comes with a sprayer. Let it sit for about 30 seconds and then it should come away with vigorous brushing. If you end up using muriatic acid, you will dilute the acid in the water, it should be mixed with 3 parts water to 1 part muriatic acid.
If the scale is on plaster or another rough surface area, pumice stones or scotchbrite pads will often do the trick. Be sure that you don’t use metal pads on a surface that this material might damage. This method is great for getting the crystals that form on top of each other off the surface of the pool. If you try this and it doesn’t do the trick, you will likely need to use the acid method we discussed above.
Calcium Prevention
It can be a real pain to remove calcium scale from your pool, especially if the problem has been left untreated for any length of time. The best offense is defense, as they say, so prevention is a great way to reduce the chances of having problems with calcium scale. If you have read many articles on our site, you probably know what is coming. Regular water testing is incredibly important for the prevention of calcium scale.
Since calcium scale is most often associated with water hardness, pH, and alkalinity levels, you want to keep a close eye on these levels when you test your water. Issues with high water hardness or elevated pH levels is an indication of an issue which, if left untreated, can result in some pretty serious calcium scale.
Keeping your pH on the lower end of the desired scale is another way to prevent the likelihood of calcium scale buildup. Pool clarifier may be a useful tool as well as it can cause calcium to clump together, which you can then vacuum, net, or allow your filtration system to clear away. Pool clarifier can have some negative impacts on your chemical balance, so you will want to use caution if you go this route.
Another great way to reduce your chances of experiencing calcium scale is to regularly vacuum your pool. If you are maintaining your pool right, you are brushing the surfaces once a week. When you do this, you may be removing calcium that could gather and scale in other places. Simply vacuuming when you brush your pool can go a long way to preventing this from becoming a problem.