Enter your pool or spa details — including pool shape, dimensions, and current alkalinity levels — and this Alkalinity Calculator tells you exactly how much alkalinity increaser you need, plus your calculated pool volume and the recommended minimum and maximum treatment range to keep your water balanced.
Alkalinity Increaser Needed
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Calculated Pool Volume
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Recommended Minimum
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Recommended Maximum
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Alkalinity Increase
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The recommended total alkalinity range is 60-180 ppm. For pools using calcium hypochlorite, sodium hypochlorite, or lithium hypochlorite, aim for 80-100 ppm. For pools using sodium dichlor, trichlor, chlorine gas, or bromine, target 100-120 ppm.
Do not add all the calculated amount at once. This can cause extreme changes in water chemistry. Add the chemical gradually over several days, testing the water regularly and adjusting as needed.
Low alkalinity can cause pH to fluctuate rapidly, leading to corrosion of pool equipment, etching of plaster surfaces, and eye/skin irritation. It also makes pH difficult to maintain.
Yes, sodium bicarbonate (baking soda) is commonly used to raise total alkalinity. Use pure baking soda or commercial alkalinity increasers, which are essentially the same product.
For rectangular pools: Length × Width × Average Depth × 7.5. For circular pools: Diameter × Diameter × Average Depth × 5.9. For oval pools: Length × Width × Average Depth × 6.7.
Different sanitizers have varying effects on pH stability. Stabilized chlorines (trichlor, dichlor) are acidic and require higher alkalinity levels to maintain proper pH buffering capacity.
Test total alkalinity at least once per week, or more frequently if you're having pH stability issues. Always test after adding chemicals or after heavy pool usage.
For aquariums, limit increases to less than 1.4 dKH per day to prevent stress. For pools, gradual increases over 2-3 days are recommended rather than large single doses.