Using a Pool Test Kit to Check Water Quality
Total Time: 30 mins.
Skill Level: Beginner
Estimated Cost: $20
Warm weather equals pool season!
That’s when it is time to check your water quality.
In a typical home swimming pool, this means routinely checking:
- Total alkalinity
- Acid demand
If you do not love chemistry, don’t worry; pool water testing kits are fairly easy to use if you follow the directions.
Working with Test Kits
Standard water chemistry tests come in several different types. The kit used for this demonstration, tests the pool water’s pH, chlorine, acid demand, and overall alkalinity. Other kits are the 2-in-1 (chlorine and pH); 5-in-1 (chlorine, bromine, alkalinity, pH, and acid demand); and 6-in-1 (chlorine, bromine, pH, total alkalinity, total hardness, and cyanuric acid).
Other kit types include testing strips or provide a breakdown through the manufacturer’s website, an app, or an online calculator. Taking a pool water sample by a pool supply store is another option. If testing your own water, always be sure to follow the instructions for your kit; which can typically be found online.
When to Test Pool Water
There is no set schedule for testing your pool water’s chemistry. Some people test daily, weekly, or even monthly and this is a perfectly acceptable. However, many pool professionals suggest the following schedule for testing:
- Chlorine levels: Two or three times a week
- pH: Two or three times a week
- Acid demand: Whenever pH levels need to be adjusted
- Total alkalinity: Once a week unless the pH has changed. A total alkalinity (TA) test should always be done if the pH changes.
- Calcium hardness: Monthly
- Cyanuric acid levels: Monthly
- Total dissolved solids (TDS): Monthly
What You’ll Need
Equipment / Tools
- Four-way pool water test kit
- Sink to wash test kit
- Towel to dry test kit
- Pool water sample
Tips for Testing Pool Water
- Discoloration on the walls of a pool often indicates the presence of algae, which requires more frequent testing and super-chlorinating (shocking) the pool.
- Don’t buy more pool chemicals than you’ll use in a season because they can lose effectiveness over time. Test solutions (reagents) typically last around a year.
- When you run out of testing solutions, you can purchase replenishment bottles rather than buying an entire testing kit.
- Testing kits are available that offer the testing solutions and materials required for nearly any chemical test you may need. These deluxe kits typically cost between $30 and $60.
Take a Water Sample
Dunk the tester into the pool, making sure you collect water from a depth of 18 inches or more for an accurate “catch.” Surface water chemistry may differ from that which is deeper in the pool.
Check the Vial Levels
Test for Free Chlorine and Residual Chlorine
Mix the Solution
Cap the vials, and turn them upside down several times to mix the solution with the pool water.
Compare the Colors
Test the Pool’s pH Levels
Test for Acid Demand
Test for Total Alkalinity
Rinse and Dry the Tester
After testing is complete, rinse clean the plastic tester in a sink (never in the pool), then dry it completely. Store the kit in a cool, dry place, away from children.