How to Use a Calcium Hardness Increaser?

Whether you have an inexpensive, bare-bones fiberglass tub or a more elaborate whirlpool or air bath, a proper level of calcium hardness is crucial to the health of your water. An out-of-whack level can lead to etching and other damages that require costly repairs.

Fortunately, it’s much easier to raise hardness than lower it. Using a calcium hardness increaser can help get your water back to safe levels. It is important to balance your calcium hardness levels.


Keeping ideal levels of calcium hardness in your pool or hot tub water is an important part of maintaining balanced and healthy pool water. Low calcium hardness levels can cause your water to become acidic, which can corrode your pool's surface and equipment. This is why we would raise calcium hardness in a pool

Using a calcium hardness increaser is one of the most effective and cost-effective ways to raise your pool’s calcium levels. These products contain calcium chloride in varying concentrations. They are typically sold in buckets and are easy to use, requiring you only to follow the directions on the label. Generally, you will broadcast the calcium hardness increaser over your pool’s surface with the pump running to ensure it dissolves completely and evenly.

It is also possible to raise your calcium hardness levels by introducing baking soda into the water. While this method works effectively, it should only be used if you have already tested and balanced the pH, total alkalinity, chlorine, and calcium levels in your pool. Adding baking soda to your water can also change the color of the skimmer basket and may interfere with the results of your test kit readings, especially if you have a blue or red endpoint (this is most commonly caused by copper from algaecides, pipes, or source water). If you notice that your endpoint turns purple when you are testing for calcium hardness, add five to six drops of the calcium hardness increaser before the indicator, buffer, and titrant. This should restore the proper reading and allow you to proceed as usual.

How to Use?

Using a calcium hardness increaser is an easy and affordable way to get your pool back on track after a water chemistry skew. You can find these products at most local pool supply stores. They generally contain the same ingredients as calcium carbonate but are usually marketed differently and are more expensive. They often come in powder form, although you can also buy liquid or granular varieties. Keep in mind there are a variety of supplies.

The first step is to test your water’s current calcium concentration. You can do this with a basic test kit that’s available at most local pool supply stores. You’ll want to ensure your water’s Total Hardness level stays between 175 and 275 ppm for best results.

Once you know your pool’s current calcium concentration, follow the instructions and precautions on the label of the product you choose to use. You can usually broadcast it directly into the pool with your circulating pump running, but some brands recommend pre-mixing it in a bucket of warm water first. This helps prevent the chemical from etching your plaster finish as it dissolves.

When you’re done, it’s a good idea to wait a day before swimming again to give the product a chance to fully hydrate into your water. After that, you can test your water’s pH and alkalinity levels using a titration kit. If your readings are within the ideal range, you’re ready to enjoy your pool again!

Where to Buy?

A calcium hardness increaser, also known as a "calcium chloride" product, is typically sold in buckets at any pool and spa supply store. It can be used to raise calcium levels that may have dropped below the safe level, which is important because low levels cause etching and corrosion of pool surfaces and equipment. In addition calcium hardness increaser can be purchased from pool supplies. In purchasing keep in mind you can buy in quantity and additional information weight can be found in the packets.

A typical calcium hardness increaser product is made of granular calcium chloride and will contain instructions that advise how much of the granules to add per 10,000 gallons of water. This product can be used in chlorine pools and hot tubs and works to prevent the etching of pool surface material as well as the corrosion of metal items such as filters, pumps, and other hardware.

The product can be added directly to the water, preferably with the pump running at high speed and should remain circulating for a minimum of 20 minutes. This is recommended as heat is generated when the product comes in contact with water, which can affect test results and the ability to achieve a specific calcium reading. The product is available in either 50 lb or 25 lb buckets, and does not require shipping by air due to its non-hazardous nature. It can also be purchased online at various online stores and is a good choice for those who want to maintain optimal calcium hardness levels in their pool or hot tub.

Who Can Use It?

The water in your pool or hot tub may look crystal clear, but there’s a concealed hazard lurking under the surface that can wreak havoc on surfaces and equipment – low calcium hardness levels. DiscountPoolSupply’s easy to use calcium hardness increaser quickly raises your pool or spa’s level so it stays within the ideal range of 200-300 ppm.

The granular formula is safe for all surfaces, including plaster and fiberglass, and will not affect the water’s pH balance. It’s sold in 50 lb. and 25 lb. pails, and can be shipped UPS Ground. Like all chemicals, it’s important to wear the proper safety gear when handling it. This includes a mask, gloves, and closed-toe shoes. It’s also important to know how much water you have so you can calculate the correct amount of calcium hardness increaser needed to balance your pool or hot tub.

Many different brands of calcium hardness increaser are available, but you should always check the active ingredient list to make sure that it’s actually calcium chloride flakes. Some products, like calcium hypochlorite (cal-hypo) are often mistakenly labeled as calcium hardness increasers, but they’re actually pool shocks designed to introduce chlorine into your water. They don’t raise your total hardness levels, but they can help reduce the formation of scale by neutralizing the acidic effects of chlorine. It’s best to add calcium hardness increaser directly to the water after treating with a pool chemical such as soda ash or baking soda.

Types of Pools

Like pH and total alkalinity levels, calcium hardness is an important aspect of balanced pool water. Keeping the level in the recommended range of 150-400 ppm is essential for preventing water from becoming corrosive.

If the pool water drops below this range, metal items including pool equipment and pool rails can become corroded. Additionally, low calcium hardness can cause etching of concrete and plaster surfaces. This type of damage is not easily repaired and can be costly to restore.

A calcium hardness increaser is a product that can be added to the pool water in order to raise the amount of calcium present in it. Typically, these products are sold in buckets and contain the compound calcium chloride. They are able to be purchased from most swimming pool retailers.

In order to use a calcium hardness increaser, follow the instructions in your pool test kit to prepare a water sample. Then, add the appropriate number of drops of the titrant to the sample and compare the color progression to the chart provided in the kit to determine your water’s calcium hardness. If a purple endpoint is obtained, this usually means interference with the titrant from metal ions in your water. In this case, it is best to retest your water. This may require several attempts before a blue reading is achieved. Count the drops of titrant used each time to get an accurate picture of your pool's current calcium hardness.

Pool or Bathtub?

When a pool's calcium hardness level gets too high, it causes the pool water to become basic and over saturated with dissolved particles including calcium. This can cause cloudy pools that are difficult to clear with regular shocks. The water can also cause scale build-up on surfaces and inside equipment that clogs them. This type of problem can be solved by draining and refilling the pool with freshwater that has a lower hardness level. It is recommended to maintain your pool calcium hardness level.

Using a calcium hardness increaser is a great way to get rid of a hard water problem without draining your pool. This product is usually a dry granular chemical called calcium chloride. It's the same thing used to melt ice and keep sidewalks safe in winter, but it's much safer for swimming pool use. It works by raising calcium levels in a pool or spa to prevent corrosion and etching of the surfaces.

The optimum calcium hardness levels in pools or spas and hot tubs are between 200 to 275 ppm. This helps prevent corrosion and etching of the surfaces and ensures proper functioning of metal parts that are submerged or touched by the water. Low calcium hardness levels can lead to corrosive water that dissolves concrete and plaster, and clogs mechanical systems. Muriatic acid can be used as a last resort to bring the hardness level up if other methods fail. However, it's far easier to bring the level up with a hardness increaser than to lower it.

To enjoy your swim in your pool or spa. It is recommended to maintain your calcium hardness levels. otherwise corrosion will occur. Proper maintenance will protect you pool surfaces, metal and extend the lifespan of your pool.

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