How to Balance and Maintain the Calcium Hardness Level in Your Pool

If your water looks cloudy or murky, it’s not an excellent sign for you as a pool owner. Swimming pool water should be relatively clear, and you’d like to keep it that way. So, if you notice something doesn’t look right in your swimming pool, it’s probably time to take action.

Because let’s face it: getting your pool chemistry right is a science. You’ve got your chlorine and pH levels in the right range, but your calcium hardness is off now — what’s the best course of action?

With our helpful guide, you’ll be able to learn about what calcium hardness is and why maintaining calcium hardness is vital to the quality of your swimming pool. I’ll also cover how to determine the right calcium hardness levels, including how to raise and lower those levels.

What Is Calcium Hardness?

In terms of minerals, water can be defined as hard or soft. If your water supply has a higher level of dissolved minerals — mostly magnesium and calcium — it’s considered hard water.

An easy way to tell if your water is particularly hard or soft is to simply feel the water with your hands. If your hands feel slimy when you rinse your hands in the water, it’s probably hard.

Usually, hard pool water looks cloudy or murky. There might also be excess calcium sediment on the surface of the water. This water scale can wreak havoc on your swimming pool in the forms of decreasing water circulation through fittings, pipes, and valves, as well as plugging the filters in your pool. If you have a heater in your swimming pool, that will most likely won’t be as efficient, and the water pump will have to work twice as hard, too.

If your pool fits that description and you’ve already tried shocking your pool a few times, chances are, your water is too hard. But is maintaining calcium hardness really that essential to your pool’s well being? Definitely.

Why Is Maintaining Calcium Hardness Important?

Although calcium itself has lots of health benefits for humans, it’s not great for your pool or for your pool’s equipment. Water that’s too hard can damage both your pool and the equipment, so you’ll need to make sure you’re maintaining that calcium harness.

Getting to the Right Calcium Hardness Levels

Calcium hardness can be a tricky business, but it doesn’t have to be. Here’s your guide to calcium hardness levels, including what the right level of hardness is for your pool, as well as how to lower and raise those calcium hardness levels.

What’s the Right Level of Calcium Hardness for Your Pool?

Well, it depends on a few factors, such as the type of pool you have. For example, if your pool is plaster or concrete, you’ll need to keep the calcium hardness around 200-275 ppm (parts per million). If it’s fiberglass or vinyl, it needs to be 175-225 ppm.

Still, just because you don’t want your water hard doesn’t mean you want it soft. Try to keep your levels balanced at all times.

How to Lower Calcium Hardness Levels

If you know for sure that your pool’s calcium hardness levels are too high, don’t fret. There are a few simple processes that’ll help you get your pool shipshape.

Replace Some of the Water (Or Use Flocculant)

If your water is high in calcium, use a filter to get the minerals out.

If you don’t want to remove some of the water from your pool, you can use pool flocculant. However, before you use it, turn off both your filter and pump before adding the flocculant. Otherwise, you’ll have to replace your filter medium if the flocculate gets in it. If your pool uses a cartridge filter, don’t use flocculant.

Flocculant is a chemical that will cause the calcium buildup to clump together. When you start seeing these clumps pop up, you can use your vacuum to remove these bits of calcium.

Use Muriatic Acid as a Last Resort

This isn’t an ideal situation, but if you’re still having trouble, try some muriatic acid. Though this chemical doesn’t lower the calcium hardness in your pool, it does increase the level of saturation, which can balance out your pool water.

How to Raise Calcium Hardness Levels

If your water turns out to be too soft, you might begin to notice some corrosion. Soft water can dissolve plaster, concrete, stone tiles, grout, and metal equipment that touches the water. This can result in pool surface repairs that can certainly break the bank if you don’t balance out your pool water levels.

Still, you should rest easy knowing that increasing the calcium hardness in your pool is a lot easier than decreasing it. You can purchase a calcium hardness increaser (like calcium chloride) to add to your pool that will raise your levels. Make sure before you buy the increaser that you know the volume of your pool so you can understand how much you’ll need.

Need Some Maintenance Help?

We partner with HomeAdvisor to help you find the best swimming pool maintenance and cleaning services in your area. Compare quotes for free from fully vetted pool professionals.

Tips for Maintaining Your Calcium Hardness Levels in the Right Range

Although calcium hardness can undoubtedly be fixed, it’s a pain when your pool water levels aren’t balanced properly. Ideally, you’ll want to maintain your calcium hardness levels in the right range at all times.

Here are our best tips for doing this.

1. Keep Your Water Levels Balanced

First and foremost, this is the easiest way to maintain your calcium hardness levels. Check your pool chemistry frequently to keep an eye out for any changes, especially with regards to calcium hardness.

2. Face Any Potential Problems Head-On

You should address any issues that might crop on as soon as you notice them. That gives you more time to make a game plan and fix them. For example, don’t wait until your water is too hard — if you see the level increasing slowly, go ahead and start problem-solving.

3. Test Your Water Regularly

You should ideally be testing your pool water on a weekly basis, especially if your water source is hard. You should also check the calcium hardness every time you drain and add new water or chemicals to your pool. If you’ve had torrential rain recently, you might want to test then, as well. The best test kits are usually liquid kits, but test strips work, too. Just make sure your test kit includes a test for calcium hardness.

4. Keep Your Pool Clean

Last but certainly not least, keep your pool clean. Cleaning your pool can go a long way in terms of preventing water hardness in the first place. If it’s stormed lately in your area and you notice debris in your swimming pool, clean it out.

If there are frogs, insects, or other previously living things in your pool, get rid of them. Keeping your pool clean is a phenomenal way of staying on top of your pool water’s chemistry levels.

Regardless, don’t let your pool’s chemistry stress you out too much. So long as you’re vigilant and observant when it comes to your pool’s water chemical levels (particularly calcium hardness, total alkalinity levels, pH, chlorine levels), you should have no problem.

And if your pool water does become too hard (or too soft), you know exactly what to do about it.

Scroll to Top