A calcium increaser is a specialized chemical utilized to raise low calcium hardness levels, safeguarding your pool surfaces from costly erosion. By bringing your calcium into the ideal range, you effortlessly extend the life of your plaster and equipment. It is a simple, proactive step for ultimate pool protection.
When pool water lacks dissolved minerals, it becomes “hungry” or corrosive. If your calcium hardness drops too low, the water will aggressively seek out the calcium it needs by literally dissolving it right out of your concrete walls, plaster, and tile grout. This creates permanent, rough pitting on the surface. Inside your equipment pad, this hungry water attacks metal components, rapidly stripping the copper out of your pool heater.
To stop this destruction, you must add a calcium increaser almost universally sold as calcium chloride (in flake or granular form).
The Ideal Calcium Ranges
Your target calcium hardness level depends entirely on the physical material your pool is made of.
| Pool Surface Type | Ideal Calcium Hardness | Why It Matters |
| Concrete, Plaster, Pebble | 200 to 400 ppm | Prevents corrosive water from etching and dissolving the surface finish. |
| Vinyl Liner | 150 to 250 ppm | Prevents metal corrosion in the pool heater and ladders. (The liner itself cannot etch). |
| Fiberglass | 150 to 250 ppm | Prevents metal corrosion and protects the protective gel coat. |
For a deeper dive into how this mineral interacts with your pH and alkalinity to dictate your overall water stability, read our comprehensive resource covering the ultimate pool chemistry guide.
Calculating Your Calcium Dosage
Because it is a heavy mineral, blindly dumping bags of calcium into your pool will likely cause you to overshoot your target, resulting in stubborn, crusty scale on your tiles.
Use the calculator below to figure out exactly how much calcium chloride you need to add based on your specific pool size:
Key insight: Never add more than 40 pounds of calcium chloride per 10,000 gallons in a single day. If your pool requires a massive adjustment, you must split the dose over two or three days to prevent turning the water into a milky, cloudy mess.
How to Safely Add Calcium Increaser
Adding calcium chloride to water creates an exothermic reaction meaning it generates an intense amount of physical heat as it dissolves. You must follow a strict safety process to avoid burns or damaging your pool surfaces.
1.Put on Protective Gear:Do not skip this.
Because the mixture gets incredibly hot and is highly alkaline, you must wear safety goggles and heavy-duty rubber gloves before handling the flakes.
2.Fill a Bucket with Water:
Fill a clean, 5-gallon plastic bucket about ¾ full with pool water first. Never pour water into dry calcium chloride, as it can boil instantly and splash violently.
3.Slowly Add the Flakes:
Gradually pour the measured calcium flakes into the bucket of water. Do not exceed 10 pounds of calcium per 5-gallon bucket to keep the heat manageable.
4.Stir and Dissolve:
Use a wooden or plastic stirring stick to gently mix the solution until the flakes dissolve. The outside of the bucket will get noticeably hot to the touch this is completely normal.
5.Pour Around the Perimeter:
With the pool pump running, slowly pour the dissolved mixture around the deep end of the pool. Immediately use your pool brush to sweep the floor, dispersing any undissolved flakes so they do not sit and burn the plaster.
Maintain Perfect Balance with DualPool
Keeping your calcium perfectly balanced prevents corrosion, but it will not stop microscopic dust, pollen, and organics from making your water look dull.
By pairing your balanced chemistry with the DualPool 2-in-1 Pool Clarifier, you ensure total water clarity. Dropping DualPool into your skimmer basket allows its self-dosing technology to continuously group together suspended solids and heavy metals. By physically pulling these contaminants out of the water column so your filter can effortlessly trap them, DualPool ensures your flawlessly balanced water also carries a brilliant, high-definition sparkle.
Frequently Asked Questions (FAQ)
Does baking soda raise calcium hardness?
No. Baking soda (sodium bicarbonate) is used exclusively to raise Total Alkalinity. It has absolutely zero effect on your calcium hardness levels.
Can I broadcast calcium increaser directly into the pool?
It is highly discouraged, especially for vinyl liner and fiberglass pools. If the heavy calcium flakes sink to the bottom and sit there, the intense exothermic heat they generate as they dissolve can easily melt a vinyl liner or permanently scorch plaster. You should always pre-dissolve it in a bucket of water.
Why did my pool turn cloudy after adding calcium increaser?
If you add too much calcium at once, or if your pH and alkalinity are already running too high, the sudden spike in calcium will cause the water to become oversaturated. The calcium precipitates out, creating a milky white cloud. Ensure your pH is balanced to around 7.2 to 7.4 before adding calcium chloride.