Importance Collecting Water Sample Test

The Importance of Collecting a Water Sample to Test

It will almost always be easier to avoid water chemistry issue than it will be to solve it. Eliminating something like an algae bloom once it already colors the water is no simple task. Once the walls are stained and the equipment corroded, the damage is done. Even worse is treating contamination. By the time swimmers or soakers complain about infections and rashes from contaminated pool or hot tub water, it is too late to prevent the spreading of disease. But, using proper sampling techniques and monitoring the chemical content of the water frequently helps you avoid costly, time consuming problems. It is incredibly important for pool operators to be familiar with good water testing kits and techniques.

Use a Sample Container

When conducting a test poolside, many people will just fill the four-in-one test bottles directly. This is perfectly fine provided you thoroughly rinse the bottle prior to collecting samples in order to eliminate any contamination and the pool’s circulation pump is running. Repeat the rinsing process between pH, alkalinity, and chlorine tests.

If you use a pool supply store to test your sample, most typically require eight ounces of water for testing. Some pool stores offer a free sample bottle. If yours doesn’t, make sure that you use a container that both meets the volume requirements and is free of contaminants. Thoroughly clean any repurposed container. Never use an empty chemical bottle, since it may throw off your sample, or pickle jars, since the salt and vinegar will never fully wash out. Also avoid coffee and juice containers as they can affect the pH reading.

Where to Gather Your Sample

Just as important as what you put your water sample in is where you get the water sample from. You don’t want to skim along the top, as that water is not an accurate representation of the entire pool. The recommended level to take your sample is 12 to 18 inches below the surface of the water, or about elbow-deep. Avoid the skimmer, return areas, and anywhere near a floating chlorine feeder to keep from getting an inaccurate chlorine reading. And, if your pool has varying depths, take the water sample from the deep end, which is less affected by temperature.

When to Take Your Sample

Something that many people don’t consider when taking a water sample is timing. Do not take a water sample if you’ve added any chemicals to the pool within the last 12-48 hours. While that may seem like a fairly large time-frame, there are a multitude of factors that may cause a discrepancy, such as the size of the pool and what chemicals you added. Most pool professionals should be able to tell you when to retest your pool’s water based on its specific circumstances. Rain also makes a difference. If it is currently raining, about to rain, or has just finished raining, do not take a water sample. After a rainstorm, wait at least eight hours to take a water sample.

Testing Your Sample

If your tests require using tablet reagents, do not touch the tablets when removing them from their foil packets. If they get wet or the foil packet tears, discard them. When using dip and read test strips, replace the bottle immediately after use; the strips can become reactive with moisture in the air. Pay attention to timing, as colors can change if you wait longer than the specified time. Follow the manufacturer’s directions carefully, since many involve more than one step.

Your samples should be fresh; taking a sample in the morning and coming back to it after going to work or running errands is not ideal. And, if you take a sample and it rains soon after, then that sample is no longer an accurate reflection of the pool.

Ensure that your testing instruments are properly calibrated and do not expose them to high humidity conditions, drop them on the pool decking, or submerge them unless they are fully sealed. It is a good idea to purchase wide range test kits since dilution testing can be a complicated and precise process.

Working with a Pool Store

If this whole process is new to you, be sure to provide basic information to your pool store, such as pool size (in gallons), pool type (fiberglass, concrete, etc.), sanitizer (chlorine, salt system), and anything that has been done to the pool in the last 48 hours.

If you want to avoid all of these hassles and ensure the water in your pool or hot tub stays balanced, consider pHin. It constantly monitors your water and tells your smartphone what you need to do to  keep the water in your pool and hot tub healthy. Use it with your own chemicals for flexibility or get our single-dose, pre-measured chemicals delivered to your door. If you need someone to service your equipment, Pool Service on Demand connects you to local, qualified pool techs.

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2 comments

  1. I appreciate your advice not to take a water sample if I have added any chemicals to the pool within the last 12-48 hours as the results may be wrong. The thing is that I did not do that, but recently I’ve noticed that my pool began to go green, and it smells so bad! I believe that testing the water from there would be the best option as I’ve checked the pool system, and everything seems to be working properly. Hopefully, the results will show how I should act in this case.

    1. Hi Steele! Sorry to hear about your pool going green, maybe you can call in a pool tech to restore the water back to healthy conditions?

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