For those who may be new to pool and spa water testing – or even if you consider yourself a seasoned pro – questions can arise regarding testing procedures. Taylor Test Kits are designed to make water testing easy, but it’s always a good idea to enrich your knowledge by reviewing tips and techniques that can help ensure success.
Follow these ten techniques every time you test to help achieve the most accurate, reliable results:
1. Read the instructions
It may sound simple, but it can be easy to assume you know how to do a test especially once you have performed it many times or if you have used similar tests. But not all instructions are the same — different manufacturers have different instructions. Also, whenever you purchase a new kit from the same manufacturer, it is always best practice to review the instructions to refresh your memory or to make sure nothing has changed. This rule applies for test kits and test strips.
2. Always take a proper water sample that is representative of the entire pool or spa
Take the water at elbow depth (18" or 45 cm) below the surface in the center of the pool and away from any return lines and corners or steps where water might not be able to circulate fully. Use a clean container provided or specified by the kit manufacturer to collect the sample.
3. Use the correct water volume for your sample
When filling a sample tube with water, you may see a curve at the surface of the water. This curve is called a meniscus. When holding the sample tube at eye level, the bottom of this meniscus should rest on the appropriate fill line for the test.
4. Never interchange reagents between different test kit manufacturers
Reagents are created based on a number of different parameters such as sample size, view depth, drop equivalence, etc. Just because a reagent has the same name doesn’t mean it’s the same strength.
5. Always hold bottles straight up and down when dispensing drops of reagent
Holding the bottle sideways or at an angle will distort the drop size, potentially creating a false result. This is especially true when testing for total alkalinity or calcium hardness.
6. Use the caps provided with your test kit to cover a vial for mixing
Don’t ever use your fingers or the palms of your hand to cover a test vial. Even though you may think your hands are perfectly clean, there are natural oils on your skin that could affect the results.
7. Never shake a sample to mix the reagents unless the instructions specifically say to do so
Shaking can actually produce a false test result. To mix properly, simply invert the sample cell a few times after capping.
8. Don’t wait to match colors unless the instructions specify a wait time
Some reagents (those that are in a brown opaque bottle) are natural oxidizers and will react quickly with heat, air, and sunlight.
9. For drop tests, use the “endpoint + 1 drop” rule to confirm you’ve reached the correct endpoint
If you’re not sure that the endpoint color is correct, add one more drop. If it doesn’t change color, then the previous drop was enough and you should record that as the total number of drops used. If the sample continues to change color, keep on adding drops until the sample stops changing color.
10. Use the proper light source for color matching
The best light to use for any color-matching test is natural sunlight. Position yourself with the sun at your back or over your shoulders — DO NOT FACE INTO THE SUN. Facing the sun will alter your eye’s ability to match colors. Remember to hold the comparator block at eye level and perpendicular to the ground — do not tilt.