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Pool Water Testing – Your Complete Guide

You’ve built your dream pool in your backyard oasis. The pool installation is complete, and the finished product is ready for use.

You’re excited to host friends this summer and maybe even your kids’ birthday parties!

Finally, your backyard is what you dreamt it would be. You feel a sense of pride and ownership over this oasis because you spent time and money building it.

Adding a custom-built backyard pool accomplishes all of those dreams. It is both the adult hangout and the kids’ second home during hot summers.

However, to ensure the best pool days for your family and friends, you’ll have to manage and upkeep your pool water by testing the water safety.

Why Should You Test Your Pool Water?

Testing your pool water is easy, but it is integral to pool ownership. Unbalanced pool water can have severe consequences for your family’s health. It also causes extensive damage to pool equipment.

Many people do not realize it, but chemical pool care is fundamental to operating a safe swimming area. Testing pool water is not a complicated process, but you need to do it at least once a week. During times of elevated use, pool owners may need to monitor pool water chemicals daily.

Outside of regular testing and upkeep, there are also times when outside forces require testing pool water more often. Reasons you might have to check your swimming pool’s water more than normal vary based on the weather and level of use.

Test your pool water more often when:

  • You’re opening your pool after an extended closure
  • Your property recently experienced a harsh storm
  • There are extended periods of high temperatures
  • You visibly notice the pool water clarity changing
  • Pool use was heavy during a short period
  • Children and pets frequent the pool

If you are considering pool installation on your property or want to learn more about testing pool water for your current pool, read below to learn the basics of pool water testing.

About Pool Water Testing

In this ultimate guide to pool water testing, you’ll learn what tools you need, what to test your pool water for, and how to add chemicals to your pool water safely and effectively.

What Is Pool Water Testing And What Tools Do I Need?

Pool water testing is the process by which you gauge the level of chemicals in your pool water. Each pool is different based on the environment and level of use, but certain chemicals need to be present at regulated levels to ensure swimmers’ safety.

There are many ways to test your pool water. Each testing tool has pros and cons. The most popular ways to test pool water are:

  • 4-in-1 Test Strips: Pool water testing strips dip right into the pool for quick and easy results. These strips are inexpensive and readily available. However, the results will not be as accurate as a liquid testing kit.
  • Liquid Testing Kits: Though liquid testing kits are generally more expensive, these kits provide more accurate readings for pool chemical levels. Testing kits give pool owners a more detailed summary of the pool water’s chemistry.
  • Digital Pool Water Testing Tools: These are the tools experts use. Digital pool water readers are very accurate when measuring pool water chemical levels. Pool owners dip the pool water monitor into the pool, and the monitor assesses the pool’s clarity. Results are reliable and instant. There are even apps that can connect to the testing tool.

Pool Water Testing Chemicals Explained

There are four main factors to monitor in your pool water. Chlorine, pH, total alkalinity, and calcium hardness are the most important levels to watch in most pools. These chemicals work closely together. It means that when one measurement is off, it is likely that another one of the four measurements will be out of the acceptable range as well.


Chlorine is arguably the most critical chemical of all in swimming pools. Because of this, it is also one of the most important chemicals to balance when testing your pool water.

Chlorine levels need to be just right for the chlorine to do its job. Chlorine acts as a sanitizer, disinfectant, and oxidizer for pool water. Once chlorine gets added to fresh pool water, it kills microorganisms and contaminants.

The pool will become cloudy or susceptible to algae growth when there is too little chlorine. When there is too much chlorine, swimmers could get irritated skin, itchy eyes, and irritated lungs.

Acceptable chlorine levels in domestic pools are between 1.5 and 2.5 ppm (parts per million.) Chlorine comes in powder, liquid, or slow-dissolving tablet form. Be sure to read the instructions on the chlorine package to ensure you add it safely. If you have questions, reach out to a professional.


pH is measured on a scale from 1 to 14. Measurements below 6 are considered acidic, and readings above 8 are considered alkaline. Ideal pool water pH is in the middle of the scale between 6 and 8.

pH directly correlates with how comfortable the pool is to swim in. When pool water is acidic and measures below 6, it can break down the pool equipment by eroding metals. When pH is alkaline or measures above 8, it can irritate a swimmer’s skin and lower the effectiveness of the chlorine.

pH and chlorine work in tandem. If your pH is balanced, your chlorine is working. If your pH is off, you also need to assess the chlorine levels.

In a 10,000-gallon pool, a ¼-pound bag of pH reducer or increaser will lower or raise pH by 0.1, respectively.

Total Alkalinity

Total alkalinity is a measurement of how alkaline your pool water is. It works in tandem with pH and is a crucial measurement that can tell you a lot about the safety of your water.

When total alkalinity is low, that means the pool pH is acidic. As a result, deposits will begin to build on the pool wall at the water line, and metal ladders or rails will get affected. If left untreated, it can eventually cause the crumbling of the pool structure. Damage to the pool structure is not only a headache but is also expensive to fix.

When total alkalinity is too high, the pH of the pool is too high. When this happens, chlorine becomes less effective. The pool water becomes murky, and bacteria can grow out of control in these conditions. High alkaline pool water poses significant health risks because of this.

An ideal measurement for total alkalinity in a domestic pool is between 80 and 120 ppm.

Calcium Hardness

Have you ever noticed a pool wall stained with white deposits? If so, you have seen the effects of calcium deposits on a pool wall.

Calcium hardness measures how hard or soft the pool water is. When your pool water test shows calcium levels are low, your pool water will suck the calcium out of the pool lining and cause irreparable damage.

When calcium hardness is high, deposits will build up on the pool siding and seep into the pool filters and pump. Often, calcium hardness gets so unmanageable that the only solution is to drain the pool. Unfortunately, draining a pool is a time-consuming and expensive fix.

Adding Chemicals to Pool Water Safely

Testing your pool water is not a complicated process, but taking the necessary precautions to ensure your safety is paramount.

Pool water chemicals each have specific special instructions.

It is imperative that you do not add all the chemicals into the pool at the same time. Mixing chemicals together causes chemical reactions and potentially chemical explosions.

To ensure your family’s safety this pool season, pool technicians recommend the steps below. Add chemicals slowly to avoid injury and damage to your pool.

  1. Test your pool water with test strips, a test kit, or a digital reader.
  2. Add any total alkalinity chemicals if needed.
  3. Add any pH reducer or increaser.
  4. Adjust calcium hardness levels.
  5. Once the pH is balanced, add liquid, powder, or tablet chlorine last to ensure its effectiveness.

Adding pool chemicals in this order is the best way to manage your pool water. It also lessens the chance that you will overuse or waste chemicals. If added in the wrong order, pool imbalances become even harder to manage. It may also be more challenging to find the origin of the pool water imbalance.

Keep Your Pool Safe This Season With Poolside Spa Services

Testing pool water is easy once you get the hang of it, but the Poolside Spa Services service team is always available to handle pool maintenance for you.

If your pool water is still imbalanced after following these steps, reach out to a trusted expert at Poolside Spa Services.

The experts at Poolside Spa Services are here to help you build the custom pool or hot tub oasis of your dreams. Contact us today to chat with an expert about your backyard lifestyle goals.

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