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For Pool Pros:   Master pool chemistry & avoid costly mistakes with our guide.   

For Homeowners:   Let HASA be your year-round Pool Partner.   


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Achieve balanced chemistry easily.

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The HASA & Orenda Calculator®

Test, Balance, and Perfect Your Pool Water — All in One Place.

Our Pool Chemical Calculator

 

The Orenda Calculator® is your go-to pool chemical calculator for achieving perfectly balanced water. Designed for professionals and homeowners alike, it simplifies how you test and treat your pool—calculating precise LSI scores, pool water volume, and chemical doses with every input.

If you’ve ever wondered how to use a pool chemical calculator, this tool makes it easy: just test your water, enter your readings, and view instant recommendations to optimize clarity, comfort, and safety.

Developed by Orenda Technologies, now part of the HASA family, the calculator reflects our shared commitment to science-based, sustainable water care. Whether you’re adjusting chlorine levels or fine-tuning alkalinity, it’s your smart LSI calculator for pools—now available directly on HASA.com. Use the embedded calculator below to get started.
Orenda app calculator on iPhone, version 4.0

The Orenda Calculator®:

 

 

The colors of the LSI

Wondering how to use a pool chemical calculator? It's color coded. At the bottom of it, the LSI number can be four different colors. From high-LSI to low:

  • (≥ +0.31) PURPLE means your water is over-saturated with Calcium carbonate (CaCO3). This is scale-forming water. The water must reject some calcium (precipitate it out) to get back down into LSI balance.
  • (0.00 to +0.30) GREEN is the ideal LSI balance. Water is perfectly happy with how much calcium carbonate it has in the current conditions.
  • (-0.30 to -0.01) YELLOW is acceptable, and close enough for the water to be happy. While green is ideal, yellow is okay. Just understand the pH will naturally rise, so depending on your pH ceiling, the LSI is likely to rise from yellow into the green, or even purple.
  • (≤ -0.31) RED is aggressive water that is hungry for calcium. It tends to etch cement, damage vinyl liners and fiberglass, and pool equipment. The lower the value, the worse! This water is starving for calcium and will try to find it wherever it can.

For the most accurate results, select “Custom” settings at the top left—this allows you to type in your exact pool readings instead of using the dials.

This LSI calculator for pools will instantly display your water’s balance, ideal adjustment levels, and estimated pool water volume, helping you achieve perfectly clear, comfortable, and well-maintained water every time.

Click inside of it and enter your numbers!

How To Use Our Pool Chemical Calculator:

  1. At the top left, select whether you prefer dials or custom inputs (tap and type in your values).
  2. At the top right, input gallons of the pool
  3. The left side is your current water chemistry. Test your water and adjust each factor.
  4. The right side is your desired water chemistry. Each number can be adjusted the same way as the left side.
  5. The goal is to adjust the right side to a green or yellow LSI value while paying attention to the pH ceiling. The pH will naturally rise to this ceiling eventually (without chemical automation). Try to contain pH so that when the pH rises to its ceiling, the LSI is still balanced in the green, not purple.
  6. Be sure your right side (desired water chemistry) is realistic, based on your current water chemistry. For example, having low calcium hardness with high alkalinity is much more difficult than basing your strategy on higher calcium hardness and lower alkalinity.
  7. Everything that is underlined can be tapped to learn more information about that item. We strongly recommend tapping each item to learn what it means.
  8. When the right side has an LSI value that works for you, tap Calculate at the bottom.
  9. The dosing results page shows the chemicals required to get from where your water is (the left side, current readings) to where you want your water to be (the right side, desired readings). Use the sliders at the top to select your chlorine type and acid type, and the dosing recommendations will adjust accordingly.

    - If you do not see any results, it's likely because you adjusted the left side last, which synced the right side dial to match it...therefore there is no difference between the dials. No difference = no result on the dosing page. Read our help article for more (The Orenda Calculator® will not show chemical doses. What's wrong?).
 

Innovation in Water Treatment Chemistry

In 2023, HASA and Orenda Technologies joined forces to advance the science of clean, balanced water. Together, we’re redefining what it means to maintain water purity—combining HASA’s trusted liquid sanitizers and sustainable packaging systems with Orenda’s data-driven approach to pool chemistry and digital tools like the Orenda Calculator®.

Our shared mission is to simplify water care for every user—from pool professionals and facility operators to municipalities and homeowners. By uniting proven chemical formulas with smart technology, we empower people to make precise, responsible water treatment decisions that protect equipment, extend water life, and create safer, healthier environments for everyone.

Today, innovation at HASA isn’t just about the products we make—it’s about the knowledge, tools, and chemistry insights we provide to help you manage water with confidence and care.

Download the Orenda app & calculator for your cellphone here:

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