Checking the calcium hardness in your hot tub is an essential part of regular pool maintenance. Water that’s too soft becomes slimy and corrosive, and water that’s too hard will get cloudy and cause buildup around your pumps and jets. Calcium hardness and water hardness are the same concept, tied into total hardness. The total hardness of your water depends on the levels of calcium and magnesium in there. Water with too much calcium is hard—unpleasant to the taste and prone to buildup. Water without enough calcium is soft—and possibly corrosive. To keep the levels in your pool or hot tub steady, perform regular water tests and use balancing chemicals as necessary. Get educated on how to adjust your hot tub’s calcium levels and enjoy clean, balanced water in your tub all season long.
Why Do Calcium Hardness Levels Matter?
Hot tubs with too much calcium in the water are recognizable by that scaly buildup on the walls. Excess calcium can also cause scale deposits in the hot tub equipment itself. The jets won’t work if there’s calcium clinging to them, and if there’s buildup in your pump, you’ll have a hard time getting water into your tub in the first place. This damage to your tub can be irreversible, so it’s important to monitor your calcium levels at all times. And if high calcium levels are wreaking this kind of havoc on your hot tub, what are they doing to you? Excess calcium makes it hard to balance the water’s pH and can irritate your eyes and skin.
That’s not to say that extra-soft water can’t be dangerous, too. When calcium levels in your hot tub water dip below 75 parts per million, the water can erode your hot tub equipment! Metal, concrete, stone, and even the grout in between can sustain damage from too-soft water. It’ll loosen up the grout around your tiles and corrode any metal pipes, pumps, or jets. The water may feel slimy to the touch—gross! Your hot tub water always needs at least some calcium in it.
How Do I Know Those Levels?
Use an easy set of test strips! Dip a strip into the water, close to the middle of the tub. (Placing it too close to a jet can give you inaccurate results.) The calcium hardness levels should be between 75 and 150 parts per million (ppm). Any basic pool or hot tub water testing kit will have a calcium hardness tester.
It’s Too Hard!
If the calcium hardness levels in your pool are noticeably above 150 ppm, the other chemicals you put in your hot tub won’t dissolve properly. The water is oversaturated with dissolved particles, including excess calcium that will build up on the walls and in the pipes. Water without enough essential minerals in it will look for those minerals wherever it can find them, including in your equipment.
If you live in an area with hard water, look for a water softener. You can find portable ones on the market that are easy to attach to value hot tubs and above-ground pools alike. That way, when you fill it, the water will be extra soft. It’s easier to balance any chemical levels in a pool or hot tub when you start off with soft water.
If you’re looking for chemical solutions, flocculants are a popular choice. A flocculant helps to coagulate those extra calcium particles in your water. Much like clumping kitty litter, flocculant will form calcium particles into visible clumps that will sink to the bottom of the hot tub. You’ll have to scoop them out with a pool skimmer or let the hot tub filter take care of them.
However, the most reliable way to lower calcium hardness levels in your hot tub water is to drain the tub and start over. Drain your hot tub, clean all the equipment to get rid of any calcium deposits, and refill it with soft water. It’s easier to add calcium to soft water than it is to remove the excess.
It’s Too Soft!
As mentioned above, it’s much easier to raise calcium levels in your hot tub water than it is to decrease them. Hot tub water that’s too soft can get slimy, foamy, and corrosive. When there isn’t enough calcium in your water, it’ll look for those minerals wherever it can find them. Avoid permanent damage to your tub by keeping steady levels of calcium in the water.
Calcium chloride is the most popular choice among pool and hot tub owners—and it’s a very powerful one. Before using calcium chloride to balance your water, check to make sure none of your other hot tub chemicals contain calcium. If not, a single product like calcium chloride will give you full and easy control over your tub’s calcium levels. Read the bottle and do some math to determine how much of the chemical to put in the water. Party-sized tubs will require a little more than a value hot tub will. Fill a bucket with water, add the calcium chloride to create a diluted solution, and pour that solution into your tub once it’s fully dissolved.
Calcium hypochlorite is known as “cal hypo” among pool and hot tub owners. People mostly use it as a shocking agent for the chlorine in your water. If you’ve got a smaller hot tub that fits two or three people, cal hypo might be a little strong. However, if you’ve got a medium-sized or large tub, consider cal hypo next time you shock your water. It’ll add calcium and make it easier to adjust the pH levels.
Next time you perform regular maintenance on your hot tub, don’t forget to check the calcium hardness levels. When those levels stay within their proper range, the rest of your hot tub maintenance will be much easier and you’ll extend the life of your tub. Make sure you’ve got the right chemicals in your tub maintenance kit to raise or lower calcium levels as necessary. Remember how to adjust your hot tub’s calcium levels when you look at all those chemicals and test strips. Use them to your advantage and keep your tub’s water healthy!