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Zodiac Calcium Up Hardness Increaser 4kg – Pool Chemical

Calcium hardness increaser for balanced pool water, helping protect pool surfaces and equipment from corrosive low-hardness conditions.

- Satisfaction Guarantee: If you are not satisfied with a product for any reason, you are welcome to return it to us for a full refund or exchange within 30 days of the purchase date - even if you have used the product. Returns are free, and we will cover return shipping.

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You are welcome to return any product for a refund or exchange. See terms below.

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Free, Easy Returns

Returns are free, there are no fees. We also make sure returns are easy to organize and processed promptly.

Satisfaction Guarantee

We stock quality pool and spa equipment and supplies from the most renowned manufactures in Australia and the world and we are confident that you will be very pleased with your purchase. If for any reason you are not satisfied with a product, you are welcome to return it to us for a refund or exchange within 30 days of the purchase date. The refund will be issued to the full amount paid for the product including shipping.

Terms

You must contact us within 30 days of the date of purchase.
The product must be returned in good conditions.
Products damaged because of incorrect use, negligence or misuse will not be accepted.
All components, accessories and original packaging must be returned.
A copy of the original receipt must be included with the return.
Products must be shipped or returned to our Penrith NSW warehouse using a pre-paid label we will supply.

If you have any questions about our return policy, please contact us on 1300 766 619 or through our "contact us" form.

How to return a product

For more details including the steps required to return a product click here

In stock

SKU

WC000420

$26.00

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Product Description

Calcium Balance for Better Pool Water Care

Zodiac Calcium Up Hardness Increaser increases calcium hardness in swimming pool water to help correct soft or low-mineral water. It is used when calcium hardness needs to be increased as part of pool water balancing.

Low calcium hardness can make pool water more aggressive, especially in concrete, tiled, pebble and plaster pools. Correcting calcium hardness helps support surface care, equipment protection and more stable water for everyday swimming.

Features & Benefits

Increases calcium hardness: Helps raise calcium levels in soft or low-mineral pool water.
Helps reduce aggressive water conditions: Supports water balance where low hardness may otherwise draw minerals from pool surfaces and grout.
Supports surface and equipment care: Correctly balanced calcium hardness helps protect pool surfaces, fittings and equipment.
Useful after refilling or topping up: Helps correct low hardness after adding fresh water or low-mineral source water.
Important for mineral-based surfaces: Especially relevant for concrete, tiled, pebble and plaster pools where low hardness can affect the pool surface.
Helps reduce foaming linked to low hardness: Low calcium hardness can contribute to foaming in pool water.

How to Use

Test the pool water to confirm the current calcium hardness level.
Calculate the required dose based on your pool volume and test result.
Dissolve the required amount of Zodiac Calcium Up in a bucket of pool water.
With the pump and filter running, apply the dissolved solution to the pool.
Run the pump and filter for at least 6–8 hours after application.
Retest the water before adding more product or making further balance adjustments.

Dosage & Coverage

Calcium Hardness Dose: Add 100g per 10,000 litres of pool water to increase calcium hardness by 10ppm.
Frequency: Maintain as required based on water test results, source water and pool surface type.

Important Usage Information

Always test pool water before dosing and follow the product label directions.
Balance Total Alkalinity and pH before adjusting calcium hardness.
Do not add Zodiac Calcium Up within 2–4 hours of adding Alkalinity Up or buffer, as this may cause very cloudy water.
Calcium is more likely to precipitate in warmer water. For larger corrections in warm water, split the dose and retest before adding more.
Calcium chloride can give off heat when dissolving. Dissolve carefully in a clean bucket of pool water and avoid splashing.
Wear protective gloves and eye protection when handling this product.
Do not overdose. High calcium hardness can contribute to cloudy water, scale and calcification.

Maintain calcium hardness at 200–400ppm for concrete pools, or 150–250ppm for fibreglass pools.

A Better Pool Experience Starts with the Right Chemistry

Zodiac pool chemicals support the key parts of everyday water care, from balance and sanitising to algae prevention, clarity, stain control and equipment protection.

Each product has a clear role in helping pool water stay cleaner, more comfortable and easier to manage, so the pool feels ready to enjoy more often.

Frequently Asked Questions

Why is calcium hardness adjusted after alkalinity and pH?

Total Alkalinity and pH have a strong effect on overall water balance. Correcting them first helps avoid unnecessary calcium adjustment and reduces the chance of cloudy water or precipitation.

Why should Calcium Up and Alkalinity Up be kept apart?

Calcium hardness increaser and alkalinity increaser can react in a way that causes extreme cloudiness if they are added too close together. Leave at least 2–4 hours between products and keep the pump running.

Why is calcium hardness especially important in concrete pools?

Concrete, tiled, pebble and plaster pools contain mineral-based surfaces. If calcium hardness is too low, the water may become calcium hungry and draw minerals from these surfaces over time.

Can low calcium hardness affect pipework or equipment?

Yes. Low hardness can contribute to aggressive water conditions that may affect pool equipment, fittings and PVC pipework over time. Correct calcium hardness helps support better equipment care.

Why can warm water cause chalky residue when dosing Calcium Up?

Calcium is more likely to come out of solution in warmer water, especially if a large dose is added at once. Splitting larger doses can help reduce the chance of chalky residue or cloudy water.

What happens if I add too much Calcium Up?

Adding too much Calcium Up can raise calcium hardness too far, which may contribute to cloudy water, scale and calcification on pool surfaces and equipment. Always test first and only add the amount required.

Do mineral pools need separate hardness testing?

Yes. Mineral pools can show higher total hardness because magnesium may be included in the reading. Calcium hardness and magnesium hardness should be checked separately so calcium is not over-corrected.

Can calcium hypochlorite chlorine increase calcium hardness?

Yes. Calcium hypochlorite chlorine adds calcium to the water over time. If calcium hardness is already high, this should be considered when choosing sanitiser or shock products.

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Specifications

More Information
SKU	WC000420
GTIN	9317545298559
Barcode	WC000420
Brand	Zodiac
Model	WC000420 - Calcium Up 4kg Box
Product Type	Pool Chemical
Shipping Type	Standard
Chemical Type	Balancers
Chemical Function	Calcium Up
Active Constituents	Calcium chloride: 990g/kg

Documentation

Shipping & Returns

Shipping

Same-day dispatch applies to orders received by 12.00 pm (AEST) during business days. Orders received after 12.00 pm and on weekends or public holidays will be dispatched on the next business day.

Delivery fees are $19.95 flat-rate per order Australia-wide, no matter how many products are in it. Orders containing bulky items like sand filters, acoustic boxes, heat pumps, pool covers, and pool slides may incur additional fees as they require specialized carriers.

Below are the estimated time to arrival in business days once an order is shipped.

Destination	Sydney	NSW	VIC	QLD	SA	WA/NT
Business Days	1 - 2	2 - 4	2 - 4	2 - 4	3 - 4	5 - 6

Rural and remote addresses, where delivery is not provided every day, may take longer.

Returns

- Satisfaction Guarantee: If you are not satisfied with a product for any reason, you are welcome to return it to us for a full refund or exchange within 30 days of the purchase date - even if you have used the product. Returns are free, and we will cover return shipping.

We take full responsibility for the safe arrival of the products that you order from us. We will replace at our expense any product that arrives faulty, damaged during transit, or is the incorrect product. Click here for details

If you have any questions about our shipping policy or our return policy, please contact us on 1300 766 619 or through our contact us form.