The Pool Calculator

The Pool Calculator helps you calculate your pool's chemical needs. Unless you are shocking your pool it is always best to add less than the full amount, wait a little while to allow the addition to mix thoroughly, and then retest and see where you are. Keep in mind that the volume of powders can vary from manufacturer to manufacturer. If you have comments or questions about The Pool Calculator please write to jason@summary.net. For help with your pool try Trouble Free Pool, a pool and spa care forum.

You are welcome to use The Pool Calculator for free. If you find The Pool Calculator to be of value please consider a donation to help support my development and web hosting expenses.

	Now	Goal		Units
Size			Mouse over a field for detail
FC			Add of % bleach. Jug size . or add by weight or by volume of . Note: Dichlor and trichlor add CYA and lower PH. Cal-hypo adds CH.
PH			Add by weight or by volume of washing soda or soda ash or add by weight or by volume of borax. Add of 31.45% muriatic acid or add by weight or by volume of dry acid. Note: PH calculations depend on TA and are approximate. They can be off significantly for large PH changes. Changing your PH will also change your TA level.
TA			Add by weight or by volume of baking soda. To lower TA you reduce PH to 7.0-7.2 with acid and then aerate to increase PH. Note: Adding baking soda will also raise your PH.
CH			Add by weight or by volume of calcium chloride or add by weight or by volume of calcium chloride dihydrate. To lower CH you replace of the water with new water.
CYA			Add by weight or by volume of stabilizer. To lower CYA you replace of the water with new water. Note: It can take stabilizer up to a week to dissolve. It will also lower your PH.
Borate			Add by weight or by volume of borax and of 31.45% muriatic acid to compensate for the PH increase. To lower Borate you replace of the water with new water.
Salt			Add of salt. To lower Salt you replace of the water with new water.
Temp			Mouse over a field for detail
CSI			Calcite Saturation Index - requires PH, TA, CH, CYA, Temp, uses Borate, Salt Less than -0.6 is suggestive of problems for plaster, tile, stone, and pebble pools. Greater than 0.6 is suggestive of problems for all pools.
Suggested FC levels			SWG: Normal: to Shock: Mustard Algae Shock: Suggested target FC levels based on the current CYA level for outdoor pools. Note: Be careful if your CYA is really and truly zero!

Estimating pool volume
A wide by long by deep pool holds .
If the depth varies, use the average depth of the pool. A good approximation is the shallow end depth plus the deep end depth divided by two. Irregularly shaped pools can be approximated by estimating the average length and width and using rectangular.

Effects of adding chemicals
Adding of will .
Note: PH calculations are not exact. These numbers are only suggestive of the relative magnitude of the PH change you can expect. Small changes, +-0.4, with PH between 7.2-7.8, TA around 80-120, and Borate near zero will be approximately correct. The further you go from those ranges the less these numbers will correspond to reality.