Total alkalinity - Alkalinity in Swimming Pools and Spas is Vital!

Total alkalinity is the measure of the ability of your pool or spa water to resist changes in the pH. This is because TA is the buffer in your swimming pool water chemistry A buffer in this case, refers to the ionic compounds that resist changes in the pH in your pool water.

Total alkalinity , is the overseer that keeps the pH of your water where it needs to be.

There are many factors that can affect the pH level of your swimming pool.

One of them is low alkalinity levels. If your buffering capabilities are too low (low alkalinity), your pH levels can swing drastically from highs to lows.

In the swimming pool industry, we call this process pH bounce. When this happens, it severely effects your water balance.

The effects of unbalanced pool water!

Whenever your pool water becomes unbalanced, it will:

  • Effect the ability of your chlorine sanitizer to kill harmful bacteria (pathogens).
  • Cause pH Bounce.
  • Cause corrosion of the metal parts in your mechanical system.
  • Cause staining of your pool or spa wall surfaces.
  • Cause scale formation in your pool.
  • Cause skin or eye irritation for your bathers.

As swimming pool and spa owners/operators, it is recommended that we keep our total alkalinity levels between 80 and 120 parts per million (ppm). At this alkalinity level, proper buffering is achieved with an ideal amount of alkaline materials in solution in the water. This is how we effectively buffer the water in our pools and spas, against any pH changes.

The effects of swimming pool water that is overly acidic!

Just in case you did not know, if your pool water becomes overly acidic (low pH levels), it will create a hungry water environment that will attempt to naturally balance itself. Your pool water will attempt this balancing process in one of two ways! These include dissolving:

  1. Some of your pool plaster, the metal parts in your swimming pool pumps, your pool filters, and your swimming pool heater.
  2. Some of the alkaline materials (total alkalinity) in your pool water.

I don't know about you, but I would rather my swimming pool water do the latter. It is much easier and cheaper, for me to replace the alkaline materials in my pool water than it is for me to:

  • Replace my swimming pool pump.
  • A pump impeller.
  • A mechanical seal on my pump.
  • One of my filter systems.
  • My swimming pool heater.
  • Re-plaster my pool.

Yes my friend, it is much more cheaper and more cost efficient.

Consequences of total alkalinity that is too low

When your pool does not have enough bicarbonate ions to buffer against your pH changes, the water will display pH bounce.

Without enough buffering capability, the smallest addition of any pool care chemicals (chlorine), will cause pH bounce.

Other factors such as acid rain or high bather loads may also cause the pH levels in your pools to fluctuate.

Low TA may cause your pool/spa water to exhibit a green tinted color, if it contains any iron or copper materials. Take a look at some of the pool and spa problems that are related to low total alkalinity levels. They include:

  • pH Bounce.
  • Etching or your pool or spa surfaces.
  • Staining of your pool/spa wall surfaces.
  • Failure of your swimming pool heater/s.
  • May also cause corrosion of the metal parts in your mechanical system/s.

If your total alkalinity level turns out to be too low, you can add sodium bicarbonate (baking soda) to bring it up to the required level. It is recommended that we add sodium bicarbonate at a rate of 1.5 pounds for every 10,000 gallons of water in our facilities. This will help us achieve a 10 ppm (parts per million) increase in TA.

The effects of total alkalinity that is too high

Straight off, when your alkalinity levels are higher than normal, often your pH levels will also be higher than normal. When this happens, your pH balance will be very difficult to balance or correct. Another good indicator of high total alkalinity is cloudy water. This is a serious problem when it comes to the water quality in your recreational facility.

Cloudy water occurs as a result of calcium carbonate being suspended in your pool water. Listed below are some of the swimming pool and spa problems that you will encounter when you have high total alkalinity. They are as follows:

  • pH Lock of your swimming pool.
  • Cloudy water in your swimming pool.
  • Rough pool and spa surfaces.
  • Clogged swimming pool filters.
  • Clogged swimming pool heater elements.
  • Reduction in you pool water circulation.
  • Possible corrosion of the metal parts in your mechanical system/s.

If your TA test reveals that it is higher than usual, you can make the necessary corrections by lowering it. This process requires you to add some form of acid to your swimming pool water. The acids that are normally used in the lowering of a pool's total alkalinity level are muriatic acid or sodium bisulfate.

In keeping up with industry standards, your alkalinity levels should always fall between 80 and 120 ppm.

If your pool or spa uses stabilized chlorine, you should maintain your TA level at 110 ppm.

However if your pool uses a different type of disinfectant (usually in granular form), then you should maintain your total alkalinity (TA) levels at 80 ppm parts per million).

The reason for the difference in the ppm, is that some swimming pool care disinfectants have a much higher pH level, while others have a very low pH level.

The sanitizers or pool disinfectants that have the high pH ranges, are the ones that will have the lower alkalinity (total) levels. This is usually the recommended 80 to 100 ppms. For disinfectants that have the lower pH ranges, they will have the higher TA levels.

This is usually from 100 to 120 ppm. Maintaining your swimming pool water chemistry is not an easy task but it has to be done and done correctly. Therefore you must at all cost, monitor and test your pool and spa water. This is the only way for you to properly maintain the level of your total alkalinity.

Total alkalinity helps ensure the safety of your swimming pool water!

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