Thanks, ‘Kara-Lynn’, for this very good question about the relationship between pH readings and alkalinity readings when testing water. A good many people have confusion on this topic!

Going back in time a bit…

Many years ago when we worked in a pool store that performed free water testing and (obviously) also sold a variety of pool water adjustment chemicals that raised the pH, lowered the pH, raised the alkalinity, or lowered the alkalinity levels of pool water we faced customers on a regular basis that had questions about the relationship between pH and alkalinity.

Quickly we learned a very simple way to explain the relationship:

• Think of alkalinity as a total number of particles that can change color in a body of water.
   
• Think of pH as the range of colors that each particle could change.
   
• If color change is required: It is easier to convince a small number of the color-changing particles to change color than it is to convince a large number of color-changing particles.
   
• If color change is unwanted: It takes more effort to convince a large number of color-changing particles to change color than it does to convince a small number of color-changing particles.
   
• Higher alkalinity means greater color (pH) stability. Lower alkalinity means less color (pH) stability.

Some people understood the meaning of my little story asked for more information on how they could test for both parameters since a clear relationship existed between pH and alkalinity.

For those folks we suggested pool water test strips like the Pool Check 5-Way and the Pool Check 6-Way test strip products as the easiest ways to keep tabs on both the pH and alkalinity of pool water.

Other people developed a blank look on their faces and simply said, “Yeah, OK, just tell me what I need to buy”… and went on their merry way.

Testing pH & alkalinity in drinking water

Can you use pool & spa test strips to test the pH and alkalinity of drinking water? Yes, but in general the manufacturers of pool & spa test strips calibrated those products using water with a higher temperature.

Therefore, we suggest using products specifically designed to test water with a cooler temperature such as the WaterWorks pH & Total Alkalinity Test Strips which come packaged in bottles of 50 tests for each parameter and cost less than $10 per bottle.

Detection ranges for the WaterWorks pH & Total Alkalinity Test Strips:

• pH: 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0
   
• Total Alkalinity: 0, 80, 120, 180, 240, 360 ppm (mg/L)

Hi and thank you for the recent post on when to test pool water. We have had our pool for only one season now and did the dumb thing of believing the pool sales jerk when he said we don’t have to test but once or twice a month. We spent a FORTUNE trying to get the water to stay clear and then when we tested more using the test strips that came with our kit the results were crazy high one day crazy high the next and the directions read like a bad foreign subtitle film. Do all pool strips get made in places outside the US? Also can test strips actually do the job or do we need something else? Thanks, May

Well, May, we DO know of several pool test strip manufacturers located here in the United States and as you probably saw in our water test kit store that at this time we carry the Pool Check Brand of pool test strips in a variety of configurations: 3-Way, 4-Way, 5-Way, and 6-Way.

We decided to carry the Pool Check Brand for a number of reasons:

• Easy-to-follow directions written right on the bottle.
   
• Pool Check test strips get manufactured in the United States by Industrial Test Systems, Inc. — which has its headquarters in South Carolina.
   
• Wider detection ranges and we believe that Pool Check color charts have more precision than many other brands currently available.
   
• We have worked in the field and at our own homes with Pool Check products for many years and have always felt confident that we could trust the water test results we got during testing.

As for whether or not Pool Check (or any pool testing product for that matter) will work well for you, that all depends on your water quality situation. If too far out of whack, then pretty much no at-home testing product will give accurate results… so we suggest taking your water at the beginning of the season (right after you open the pool) to a local pool store and having them test it — so you can hopefully start the season off right..

Yes, they will more than likely tell you that you need this, that, and the other thing to get your water balanced, but at least you will know that you have done what you needed to do to get the water balanced, clear, and safe. Follow their instructions and then use products like the Pool Check brand of test strips to make sure important water quality parameters have not started to drift from acceptable levels.

In our opinion, a properly monitored pool should rarely, if ever, have any serious algae or clarity problems stemming from water quality unless outside factors (i.e. chemical feeder malfunction, excessive bather load, kids forgot to add chlorine for a week, etc.) come into play.

Moral of the Story?

Start your swimming season the right way by having your water tested by a trained pool water professional. They will (or should…) test for more advanced things like metals (i.e. iron, copper, TDS, etc.) and get you headed in the right direction with crystal clear water that’s safe for swimming.

After that, use the water testing product that makes the most sense for your budget and water conditions to keep an eye on the quality of your water. By doing so you should have the ability catch potential water quality issues before they become… expensive water quality problems.