HTH PLUS Calcium Hardness Increaser, in a practical 25 lb bag, is the smart choice for keeping pool water balanced and protecting your pool surfaces and equipment. This dedicated calcium hardness increaser raises calcium levels to the optimal range, helping prevent surface damage and corrosion that soft water can cause over time.
Why calcium hardness matters in your pool
Low calcium hardness can lead to etching, rough plaster, and unnecessary wear on metal components. By maintaining appropriate calcium levels, you create a stable water balance that enhances the longevity of your pool finish, reduces maintenance headaches, and supports overall water quality. This is especially important for plaster and concrete pools that are more sensitive to hardness fluctuations.
What makes HTH PLUS stand out
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Economical 25 lb container designed for ongoing maintenance in mid- to large-size pools
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Formulated for quick dissolution and even distribution as the circulation system runs
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Trustworthy HTH brand with the PLUS sub-brand pedigree, backed by years of pool chemistry know-how
- Specifically designed to raise total calcium hardness without altering your pH balance when used as directed
Simple, effective use in real life
Use this product when test results show calcium hardness below the recommended range for your pool type. With the circulation system on, broadcast the dosage around the pool perimeter or near returns, then allow the water to circulate and re-test after several hours. Always follow the label directions for dosage amounts and safety guidance. This approach minimizes overshoot and helps you reach a stable hardness level more predictably.
Who benefits most
Ideal for pools with soft-fill water, plaster, or concrete surfaces, and for anyone looking to protect their equipment from the effects of low calcium levels. Suitable for both in-ground and above-ground setups where balanced water chemistry is critical for long-term durability and enjoyment.
Practical tips for best results
- Pair calcium hardness maintenance with regular pH and total alkalinity checks for a balanced triad of pool chemistry
- Test water at least weekly during the swim season, and after heavy rainfall or dilution events
- Store the 25 lb bag in a cool, dry place to preserve its effectiveness
