Calculators - Further Reading

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Calculators for Pool Maintenance

At TFP we believe pool maintenance should be based on science and physics. There are many underlying calculations that go into TFP recommendations and advice. Below are some tools to allow you to make your own calculations and see the effects on your pool.

Pool Math

Pool Math makes it simple to track all of your Pool Test Logs and takes all of the guess work out of how much chemical you need to add.

Pool Math calculates the quantities of chemicals required for adjusting chlorine, pH, alkalinity, calcium, CYA, salt, and borates. It also calculates the Calcium Saturation Index if you log the water temperature.

You need to enable tracking of CSI, salt, borates or water temperature under the round hamburger option icon.

Pool Math also calculates the effects of adding a chemical and calculates the normalized price of bleach/chlorine so you can compare the value of products with different chlorine percentages and quantities.

Pool Water Evaporation Rates

This Water Evaporation spreadsheet will calculate the evaporation rate given air and water temperature, relative humidity, and wind. Note that this is the wind speed at the surface of the water which is usually quite a bit lower than general wind speed due to fences and the water being somewhat below ground level.[1]

For more read Evaporation of Pool Water.

Heater Run Time and Cost Calculator

This Heating Runtime and Cost spreadsheet[2] contains:

  • A Scratch Pad where you can estimate the hours needed to run the heater to achieve a desired temperature rise for a given water volume. There is a Multiplier Factor to account for variability in heating water that is subject to the elements. This is explained further in the spreadsheet.
  • A Cost Estimator where you can select the billing unit from a drop-down list, cost per billing unit, heater BTU, and number of hours the heater is run. For the number of hours, you can use either the hours calculated in the Scratch Pad or enter your own figure. The spreadsheet calculates cost by taking the cost per billing unit and dividing it by the number of BTUs in that billing unit to arrive at a cost per BTU. It then takes the cost per BTU and multiplies that by the Gross BTU output of the heater to get the cost per hour to run the heater. The cost per hour is then multiplied by the number of hours the heater is run to arrive at the Total cost to run the heater for X hours.

The spreadsheet is set up to use with Natural Gas heaters. It estimates the variable usage-based cost that appears on your bill. Fixed costs that appear on your bill are not factored into cost calculations since, by definition, a fixed cost is static and would appear on your bill as the same amount each month regardless of consumption.

When using the runtime for Heat Pumps put the Heat Pump BTU's in the Net heater BTU field instead of reducing it by 20% for natural gas heater efficiency loss.

For calculating heat pump costs vendors like Pentair has a Heat Pump Calculator to determine the appropriate size Heat Pump for your location.

This spreadsheet loads in Excel .xls 2003 format but should be saved in .xlsx format.

Estimating Pool Volume

If you need to get an estimate of the amount of water in your pool you can use the calculator at the bottom of the old [Pool math web page]. You simply enter the pool dimensions and average depth and it gives you the gallons of water int he pool.