Common Mistakes Made Testing Water Chemistry

6 Common Mistakes Made When Testing Water Chemistry

Learn more about pHin, the Smart Water Care solution for pools and hot tubs.

You have to test your pool and/or hot tub’s water chemistry to make sure the water is balanced and safe for swimming. Unfortunately, testing errors occasionally occur, even with experienced testers.

The following testing errors are the six we see most often, and what you can do to guard against making them.

  1. Contamination

Contamination makes test results unreliable, and it happens easily. Oily, wet, or dirty fingers, a dirty test vial, even the humidity in the air can void your test results. Luckily, a few safety habits help guard against contamination.

First, close reagent containers tightly after every test, and never use reagent caps interchangeably. Second, remember that fingers make poor stoppers, use the designated test kit vial caps to cover the vials. Next, keep reagent pads from running into each other by holding test strips horizontally. Finally, thoroughly rinse test residue and wipe clean after each use.

  1. Timing

Pay attention to how long you allow test samples to sit, especially the sanitizer residual, which can change from a valid to a false reading quickly. Read the instructions carefully, looking for the required reagent wait time. Nearly every chemical test is time-sensitive, so mark time accordingly.

  1. Follow the Directions

This should be a given, but wow, it really needs saying: Follow the Directions.

Read the directions whenever you buy a new testing kit. Manufacturers occasionally change instructions. What’s more, they differ from brand to brand. It is also incredibly easy to leave out a step, so take the time to read the instructions, every time you test the water.

The instructions should tell you how much water to use, how long to let it sit, the angle to hold the sample, and the best method to dissolve the reagent.

  1. Sample Volume and Location

Pay close attention to the fill line on your sample tube, and watch out for air bubbles, which cause improper fill. If using a liquid reagent, ensure the drop size is correct and that you hold the reagent bottle fully inverted vertically. This provides for full drops, while holding the reagent bottle at an angle will provide less of a drop thus possibly resulting in an incorrect reading.

Always collect your sample from the same location in your pool or hot tub. In a pool, this is the midway point between the deep and shallow ends. In both pools and hot tubs, avoid collecting water from the surface or near a return line. Instead, insert a clean, plastic bottle, facing down. This traps air within the bottle, keeping it from taking water too close to the surface. Once your elbow hits the water, turn over the bottle, letting it fill with water.

  1. Check Your Expiration Date

Assuming you stored your testing materials correctly, they should be good until the expiration date listed on the packaging, typically the test solutions are accurate for 1 year if stored in a cool and dry environment. In addition, date the materials yourself before storing them. Since heat and sun cause reagents and test strips to go bad (as does storing them incorrectly) it is recommended you store your kit / vials in a home where the temperature is controlled.

  1. Lighting Matters

Whenever possible, conduct your tests in natural light, without wearing sunglasses. Artificial light and sunglasses throw off color perception. In addition, close the sample chamber, as sunlight interferes with test results. Similar to photography, have the sun at your back and use the “white” card supplied with most quality kits or a piece of white paper behind the vials or strip to get a more accurate hue of the colors you are comparing.

If you want to avoid all of these hassles and ensure the water in your pool or hot tub stays balanced, consider a pHin smart monitor. This little device constantly monitors your water and automatically sends you the exact chemicals you need to keep the water in your pool and hot tub healthy. If you need someone to service your equipment, Pool Service on Demand instantly connects you to local, qualified pool techs.

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1 comment

  1. I did not know that typically the test solutions are accurate for 1 year if stored in a cool and dry environment, and I totally agree that all the chemical testing materials should be destroyed after the expiration date. I need a chemical testing service for my small company as I am going to produce creams, and having such a service involved is logical. I will make sure all the materials are stored and managed properly.

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