The Pool Calculator • Pool School • Trouble Free Pool

The Pool Calculator, http://www.poolcalculator.com/, is a handy web-based tool that does all of the calculations required to maintain your pool. The Pool Calculator can figure out the amounts of chemicals to add, what appropriate FC levels are for your CYA level, what your calcite saturation index is, and help you estimate your pool volume. It is also possible to make a local copy of the Pool Calculator web page, and use it without an Internet connection.

To figure out the amount of a chemical to use, enter your pool volume in the orange size field near the top, enter your current test results in the "Now" column and your desired levels in the "Goal" column, then hit tab, or press the Calculate button, to see what you need to do to get to your goal levels.

For every level except FC, it is usually best to approach your goal level gradually, instead of adding the full amount all at once. This is especially important with CH and CYA, which are much easier to raise than to lower: be careful not to add too much. There will always be small errors in your pool size, test numbers, and chemical measurements, which will result in levels coming out slightly different from what The Pool Calculator says.

To calculate the number of gallons in the pool, look for the "Estimating pool volume" section, towards the bottom of The Pool Calculator page. That calculation requires you to enter an average width, length, depth, and basic shape. If the width, length, or depth of your pool varies, you need to estimate the average number. If your shape is not listed, you need to either divide the pool up into sections that match one of the available shapes or select the closest available shape.

It is common for a pool to have more than one depth. If you have a shallow end and a deep end, you can measure each and average the two numbers to get an approximate average depth. For irregularly shaped pools the same thing can be done for the width and length: measure in a couple of places and average the results. For L shaped pools, you can divide the pool into two rectangular sections, calculate the volume of each, and total the two volumes.

The Pool Calculator can suggest appropriate FC levels based on your current CYA level. Enter your current CYA level in the "Now" column of the yellow CYA row and press tab or click on Calculate. The Pool Calculator will then suggest appropriate FC levels in the blue "Suggested FC levels" section towards the bottom.

The "SWG" level is appropriate for day to day use with a salt water chlorine generator. The "Normal" range is suitable for day to day use when using other sources of chlorine. Be sure to keep the pool's FC level at or above the SWG level, or lower end of the normal range, as appropriate. "Shock" level is for when CC is greater than 0.5 or you have algae. The higher "Mustard Algae Shock" level is sometimes required when fighting persistent mustard algae.

The Pool Calculator can also calculate your calcite saturation index (CSI). Enter all of your available test results and look in the green CSI row, towards the bottom, for your "Now" and "Goal" CSI numbers.

The Pool Calculator takes care of all of the math required for pool maintenance, leaving you more time to swim.