Pool Calculators

All pools and spas need maintenance. We at Hines Pools & Spas are here to help you determine just what kind and amount of maintenance your pool or spa needs. Our handy calculator will take you step by step how to figure out amounts of chemicals needed to keep your pool or spa crystal clean. All you need are the dimensions of your pool and spa.

To determine the proper amount of chemicals to use for your pool, you will first need to calculate how much water it holds. Use these pool volume calculators to find the volume of your pool.

Calculate Volume

Shallow Depth
Deep Depth

Most pools are not perfect rectangles. Estimate volume by fitting the best rectangle that will cover your pool. Reduce or increase the volume calculated by 10-20% as appropriate to your pool.

Round Pool or Spa Volume Calculator

Avg Depth

Test Kit Readings & Adjustments

Free Chlorine (ppm)
Total Chlorine (ppm)
Total Alkalinity (ppm)
Calcium Hardness (ppm)
Shock Required (lbs of Cal Hypo 65%)
Add Sodium Bicarb (lbs.)
Add Cal Chloride (lbs.)
Add Soda Ash (lbs.)

Add only if Total Alkalinity is above 100 ppm.

Lowering or raising pH:

Maintaining proper Total Alkalinity helps maintain the correct pH. Always adjust TA before trying to adjust pH. If your TA level is too high, call us for advice on how to use acid to lower it. This can be a tricky procedure and is best left up to experienced professionals to achieve good results without damaging your plaster.

If pH is too high and alkalinity is correct:

use an acid demand test from your test kit to determine how much acid to add to your pool. If you don't have this test, you can add 2 cups of muriatic acid per 10,000 for every tenth of a point that you need to lower pH. This is approximate. Retest pH a few hours after adding acid. Always add acid to water - never water to acid.

Langelier Saturation Index

The Langelier Saturation Index (LSI) is a formula developed from studies conducted by Dr. Wilfred Langelier in the early 20th century. The LSI is the basis for water balance and saturation, and this article will try to explain how it works in a simplified way. This is complex science, but very helpful to know as a pool owner or operator. See this page on one of our partners, Orenda Technologies, on how to calculate the LSI for you pool. Calculate LSI