Total Alkalinity For Your Swimming Pool

Total Alkalinity (TA)

If the water in a pool becomes overly acidic (the pH gets too low), the water becomes “hungry” and attempts to balance itself. It can balance itself in one of two ways:

1. It can dissolve some of the plaster, and the metal parts in the pump, filter and heater.
2. It can dissolve some of the alkaline materials (total alkalinity) in the pool water. Obviously,this is the preferable way to go, because it is a lot easier to replace the alkaline materials in the pool water than it is to replace the pump, filter, heater, or plaster.

Ideal Alkalinity will buffer pH swings so they do not attack the plaster or cause the pH to fluctuate excessively. A good TA reading is between 80 and 120 and helps to protect the water against pH changes.

Low Alkalinity (under 80) will cause the pH to swing up and down fairly wildly and damage the pool or equipment over time.

High Alkalinity (over 120) may cause the water to cloud up because the water is oversaturated and there is only so much material that it can absorb

The use of Sodium Bicarbonate (baking soda) can be used to raise the TA level, while Pool Acid is used to lower TA. Once you establish a consistent chemical balance after weekly testing, your TA level should stay relatively constant.

Note: Do not add more than 1 gallon of Pool Acid per 10,000 gallons of water at one time. If the pool requires more than this, add the maximum amount then retest 12 hours later and make further adjustments. This will help to keep you from over-treating the pool.

Testing Alkalinity Levels

The Total Alkalinity test involves the use of three reagents for a proper reading.

1. Fill the large TAYLOR test vial to the 25 ml mark with pool water and add 2 drops of R-0007 to neutralize the chlorine in the water. If your chlorine level is above 5 ppm, add one more drop in order to neutralize the chlorine.
2. Add 5 drops of R-0008 to the sample and swirl until you see a consistent green.
3. Add R-0009 drop by drop, swirl the water and count the drops until the sample turns from green to red. Multiply the number of drops by ten to get the total alkalinity reading. i.e: 10 drops = 100 ppm.
4. A good TA reading is between 80 and 120 and helps to protect the water against pH changes.

Note: If the chlorine level is high, the color may flash from blue to yellow instead of green to red. This can be solved by adding more neutralizer as described above, and then test again.

Adjusting Total Alkalinity - pH and Total Alkalinity (TA) adjustments can affect each other. Always correct TA first, then pH.

Raising Low TA levels (under 80) - With pump on, add about one scoop of a pool measurement scoop (app. 20 oz) of Sodium Bicarbonate into the skimmer, or, pour it around the edge of the pool in the deep end. Don’t pour it all in one place or it will cloud the water. Test in about an hour and add more if needed.

Lowering High TA levels (over 120) - Add one quart of Pool Acid at a time (one quarter of a gallon bottle) around the deep end of the pool and away from the return jets. This creates pockets of low pH, burns off alkaline materials, and brings down the TA without significantly lowering the pH. Check in about an hour and note the difference from your original reading. Keep adding pool acid in small increments until you reach the proper TA level.