How much liquid chlorine do I need to raise free chlorine by 1 ppm?

It depends on your pool volume and the strength of the chlorine. For 10.5 percent sodium hypochlorite, roughly 10.7 fluid ounces per 1 ppm per 10,000 gallons. Use the Pool Volume calculator first, then the Liquid Chlorine Dose and Free Chlorine Adjustment calculators, entering your current and target ppm. Weaker 6 percent household bleach needs nearly double the volume for the same rise.

What is a good turnover rate for a commercial pool?

Most health codes require a 6 hour turnover for public pools and much faster for spas, often 30 minutes. The Water Turnover Rate calculator divides total gallons by pump flow in gallons per minute to give the hours per full cycle. If your Pump Flow Rate cannot hit the required turnover, you either need a larger pump or must reduce bather load. Spas turn over fastest because bather density is high.

Why is my chlorine not holding even though I keep adding it?

Usually cyanuric acid is too high or you have chloramines consuming the free chlorine. Check the Cyanuric Acid Adjustment calculator; above about 100 ppm, chlorine gets over-stabilized and loses effectiveness. If combined chlorine is above 0.3 ppm, run the Combined Chlorine Breakpoint calculator to find the shock dose needed to oxidize chloramines. High bather load and sunlight without stabilizer also burn chlorine fast.

How do I use the LSI to know if my water is corrosive or scaling?

The LSI Water Balance calculator combines pH, temperature, calcium hardness, total alkalinity, and TDS into a single index. A value near zero is balanced; below minus 0.3 the water is corrosive and will etch plaster and dissolve metal, while above plus 0.3 it will scale and cloud. Adjust the inputs using the Calcium Hardness Adjustment and Total Alkalinity Adjustment calculators until the index sits between roughly minus 0.3 and plus 0.3.

How do I set a chemical feed pump for muriatic acid or chlorine?

Start with your target dose in ppm and pool volume to get the total chemical needed, then the Chemical Feed Pump Setting calculator converts that into a pump output in gallons or milliliters per hour over your run time. If you feed diluted acid, use the Chemical Dilution and Stock Solution Strength calculators to confirm the concentration in the day tank so the pump delivers the right active amount.

How much water do I lose to backwashing and evaporation?

Backwash Water Volume depends on filter size and flow; a typical sand filter can dump several hundred gallons per cycle. The Evaporation Water Loss calculator estimates daily loss from surface area, temperature, humidity, and wind, often a quarter inch or more per day on an outdoor pool. Add both to bather splash-out and the Make-up Water Rate calculator tells you the fresh water you must replace, which also dilutes your chemistry.

Manufacturing calculator category

Pool, Spa & Water Treatment Chemistry calculators

This category covers the water chemistry and hydraulics math behind running pools and spas, from figuring out how many gallons a body of water holds to dosing chlorine and correcting pH, alkalinity, and hardness. It is built for pool service techs, commercial aquatic operators, and facility maintenance staff who need dose amounts and flow figures they can act on the same day.

What this hub covers

Calculators for pool and spa operators covering volume, sanitizer dosing, water balance, turnover, filtration, chemical feed, and operating cost.
Browse pool, spa & water treatment chemistry calculators for manufacturing planning, quoting, quality, capacity, and operations decisions.

Best calculators in this category

Pool Volume: Estimate pool water volume from average length, width, depth, and a shape conversion factor.
Spa Volume: Estimate spa or hot tub volume from shell dimensions, average depth, and a shape factor.
Liquid Chlorine Dose: Estimate liquid chlorine needed from pool volume, desired free-chlorine rise, and product strength.
Chlorine Tablet Feed Rate: Estimate chlorine tablet feed rate from pool volume, daily chlorine demand, tablet yield, and feeder efficiency.
Free Chlorine Adjustment: Calculate the free-chlorine gap between a target residual and current test after planned treatment credits.
Combined Chlorine Breakpoint: Estimate breakpoint oxidation demand from combined chlorine, a breakpoint multiplier, and delivery efficiency.
pH Adjustment: Estimate remaining pH correction from target pH, current pH, and planned chemical response.
Total Alkalinity Adjustment: Calculate the alkalinity gap between target total alkalinity and current test after planned corrections.
Calcium Hardness Adjustment: Calculate the calcium hardness gap between target hardness and current water test.
Cyanuric Acid Adjustment: Calculate cyanuric acid adjustment needed from target stabilizer, current CYA, and planned treatment.
Salt Pool Salt Addition: Estimate salt required from pool volume, desired salt increase, and salt purity.
Water Turnover Rate: Calculate daily water turnovers from pump flow rate, pool volume, and daily runtime.

Common manufacturing problems solved

pool chemistry calculator
spa chemistry calculator
chlorine dose calculator
pool volume calculator
pool pH adjustment
alkalinity calculator
pool turnover rate
chemical feed pump setting
water treatment calculator
pool chemical cost

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Category questions

How much liquid chlorine do I need to raise free chlorine by 1 ppm? It depends on your pool volume and the strength of the chlorine. For 10.5 percent sodium hypochlorite, roughly 10.7 fluid ounces per 1 ppm per 10,000 gallons. Use the Pool Volume calculator first, then the Liquid Chlorine Dose and Free Chlorine Adjustment calculators, entering your current and target ppm. Weaker 6 percent household bleach needs nearly double the volume for the same rise.
What is a good turnover rate for a commercial pool? Most health codes require a 6 hour turnover for public pools and much faster for spas, often 30 minutes. The Water Turnover Rate calculator divides total gallons by pump flow in gallons per minute to give the hours per full cycle. If your Pump Flow Rate cannot hit the required turnover, you either need a larger pump or must reduce bather load. Spas turn over fastest because bather density is high.
Why is my chlorine not holding even though I keep adding it? Usually cyanuric acid is too high or you have chloramines consuming the free chlorine. Check the Cyanuric Acid Adjustment calculator; above about 100 ppm, chlorine gets over-stabilized and loses effectiveness. If combined chlorine is above 0.3 ppm, run the Combined Chlorine Breakpoint calculator to find the shock dose needed to oxidize chloramines. High bather load and sunlight without stabilizer also burn chlorine fast.
How do I use the LSI to know if my water is corrosive or scaling? The LSI Water Balance calculator combines pH, temperature, calcium hardness, total alkalinity, and TDS into a single index. A value near zero is balanced; below minus 0.3 the water is corrosive and will etch plaster and dissolve metal, while above plus 0.3 it will scale and cloud. Adjust the inputs using the Calcium Hardness Adjustment and Total Alkalinity Adjustment calculators until the index sits between roughly minus 0.3 and plus 0.3.
How do I set a chemical feed pump for muriatic acid or chlorine? Start with your target dose in ppm and pool volume to get the total chemical needed, then the Chemical Feed Pump Setting calculator converts that into a pump output in gallons or milliliters per hour over your run time. If you feed diluted acid, use the Chemical Dilution and Stock Solution Strength calculators to confirm the concentration in the day tank so the pump delivers the right active amount.

Last reviewed 2026-05-12.