PoolMath

PoolMath takes care of all the math that can come up while you are working at keeping your swimming pool's water chemistry in balance, telling you how much of each chemical to add. For an introduction to using PoolMath see this article. If you have comments or questions about PoolMath please post in the Chemistry 201 section of the forum. For help with your pool try the Just Getting Started area of the forum, or another section as appropriate.

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NowTarget Units 
Size Mouse over a field for detail
FC
Goal:
Not Setup
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
Goal:
Not Setup
Given TA of and Borate of :
Add by weight or by volume of washing soda or soda ash
or add by weight or by volume of borax.
Add of muriatic acid
or add by weight or by volume of dry acid.
Note: pH calculations depend on TA and Borate. Results are approximate and can be off significantly for large pH changes. Changing your pH will also change your TA.
TA
Goal:
Not Setup
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 just a little.
CH
Goal:
Not Setup
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, with CH of .
CYA
Goal:
Not Setup
Add by weight or by volume of stabilizer
or add of liquid stabilizer.
To lower CYA you replace of the water with new water.
Note: It can take solid stabilizer up to a week to dissolve. It will also lower your pH.
SaltAdd of salt.
To lower Salt you replace of the water with new water.
BorateAdd by weight or by volume of
and of 31.45% muriatic acid to compensate for the pH increase.
To lower Borate you replace of the water with new water.
Note: The pH should be tested and adjusted as needed after increasing the borate level.
Temp Mouse over a field for detail
CSICalcite 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! With CYA above 90 we recommend replacing water to get CYA down before you start the SLAM process.
Suggested Goal Levels Use suggested goal levels from:
Primary source of chlorine: Pool surface:
Note: Suggested goals are simply a starting point. There are many situations that are not covered by these basic guidelines.

Notes
Unless you are SLAMing 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 to see where you are. Also, keep in mind that the volume of powders can vary from manufacturer to manufacturer.

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 pH changes will correspond to reality.

Copyright © 2007-2010 by Jason T. Linhart. Copyright © 2013-2015 by TroubleFreePool.com. All rights reserved. Updated, September 17 2015.