AquaChek 4 in 1 Test Strips for Pool and Spa

Tests Free Chlorine, pH, Total Alkalinity, Stabiliser


Optional Extras

Swimming pool test strips from Aquachek.

Comes in a pack of 50. Tests for pH,  free chlorine, TA & stabilizer. Can be used for a pool or spa.

pH Testing

We use pH as an index to express how acidic or basic a solution is. (The scientific definition of pH is “the negative logarithm of the hydrogen ion concentration”.) A pH greater than 7.0 is basic, and a pH lower than 7.0 is acidic. In pools and spas, it is important to maintain the water in the slightly basic range of 7.2 to 7.8. The National Spa and Pool Institute (NSPI), the industry association in the United States, has set a standard of 7.2 to 7.6 as the ideal pH.

If pH Is Low:

  • The water can corrode surfaces, metal equipment or fixtures.
  • Swimmers and bathers can experience discomfort from burning eyes and itchy skin.
  • The chlorine may dissipate more quickly.
  • The water may cause pitting and etching of plaster surfaces.

If pH Is High:

  • Calcium and metals tend to come out of solution (the opposite of dissolving) at high pH levels, creating the potential for staining and scale formation. The calcium and metals will actually create deposits and discoloration on pool walls and equipment.
  • Swimmers and bathers can experience discomfort from burning eyes and itchy skin.
  • High pH can contribute to cloudy water.

Free Chlorine test

Every sanitizer has two key functions, to sanitize (kill bacteria and all living organisms) and also oxidize (destroy contaminants and waste). The most popular pool and spa sanitiser is chlorine. Chlorine is also classified as a disinfectant, meaning that it is capable of killing bacteria, algae and other organic material instantly. All chlorine does the same thing when it is added to the water, regardless of the type of chlorine added. It forms free available chlorine. Free chlorine is the form of chlorine that kills bacteria, algae and disease-causing organisms. It is the attack dog that guards your pool against macrobiotic intruders. (In general, you wouldn’t want a dog in the pool, but this is an exception.)

You must maintain free chlorine at a sufficient level to disinfect potential contaminants on contact. The more chlorine in the water, the more it can sanitize and oxidize the water. (Remember that sanitizing and oxidizing are the processes that chlorine uses to keep the water clear and clean.) However, if the free chlorine level gets too high, it can make the water uncomfortable for swimmers. The trick is to keep the free chlorine level in the ideal range. In a swimming pool, keep free chlorine at a minimum of 1 ppm (parts per million) and a maximum of 10 ppm, with an ideal concentration of 1 to 3 ppm.

In spas, the level needs to be maintained at a slightly higher level due to the smaller volume and higher temperature. The minimum level should be 2 ppm in a spa, again no higher than 10 ppm, and ideally 3 to 5 ppm.

Total Alkalinity Test

Total alkalinity is the measure of the amount of alkaline buffers (primarily carbonates and bicarbonates) in your water. These alkaline substances buffer the water against sudden changes in pH. Total alkalinity is considered the key to water balance. It is the first parameter you should balance when making routine adjustments to your water.

If you neglect to check the total alkalinity in your pool or spa, you may have trouble balancing the pH. You may also notice that pH fluctuates suddenly despite your best efforts to keep it in the ideal range. If the alkalinity is too low, anything introduced to the water will have an immediate impact on pH. Abrupt shifts in pH can cause scaling or corrosion of metal equipment and fixtures as well as other problems. When the total alkalinity is high, the pH has a tendency to drift upward, causing scale to form.

Maintaining an ideal level of alkalinity will protect your pool or spa and its equipment from the harmful effects of sudden pH fluctuations. Think of the alkalinity as training wheels: it keeps the pH in balance without allowing it to tip too far to either side. Of course the pH can still drift upward or downward, but that change will happen gradually as long as the alkalinity falls within the ideal range. The ideal range of total alkalinity for pools and spas is between 80 and 120 ppm (mg/L).

When the total alkalinity is too low, add sodium bicarbonate. If the total alkalinity is too high, you can lower it by using muriatic acid or sodium bisulfate

Cyanuric Acid (Stabilizer) test

The sun’s ultraviolet (UV) rays will make the chlorine in an outdoor pool dissipate quickly. In fact, an ideal level of chlorine in an “unstabilized” pool or spa can be lost in less than two hours on a bright sunny day, due to the UV rays of the sun. Cyanuric acid acts as a “stabilizer” that helps chlorine hold up better when exposed to the UV rays. You can think of cyanuric acid as blocking the effect that the sunlight has on breaking down the chlorine—kind of like a sunscreen for your pool.

You should maintain an ideal level of cyanuric acid, 30 to 50 ppm (mg/L), to prevent rapid chlorine loss. If the cyanuric acid level is too low, you may need to add more to the water. However, be advised that cyanuric acid will make the pH of the water lower (more acidic), so you may have to adjust the pH upward as well.

On the other hand, too much cyanuric acid will reduce the beneficial effect of your chlorine, leading to stains or cloudy water. Some chlorine compounds already contain an amount of cyanuric acid. If you are using dichlor or trichlor as your primary chlorine sanitizer, you are already introducing cyanuric acid along with the chlorine. If the cyanuric acid level is your pool or spa is too high, you will need to partially drain and refill with fresh water.

When you first fill your pool or spa, test the cyanuric acid level until you have added enough to reach the ideal range. After that, test cyanuric acid a minimum of once a month throughout the pool season. If you are using dichlor or trichlor, you will have to test cyanuric acid more frequently to ensure that the level has not exceeded the upper limit.

 When purchasing, tap the edit cart link to see what freight you pay.



Be The First To Review This Product!

Help other Direct Pool Supplies users shop smarter by writing reviews for products you have purchased.

Write a product review

We Also Recommend

Others Also Bought

More From This Category