Total Alkalinity (TA) measures the concentration of alkaline substances, primarily bicarbonates, dissolved within pool water. Maintaining appropriate TA levels is necessary for preserving the overall health and quality of the swimming environment. This parameter directly influences the stability of the water chemistry, affecting both bather comfort and equipment longevity. This guide provides pool owners with practical, step-by-step instructions for increasing Total Alkalinity when levels are found to be low.
The Role of Total Alkalinity in Pool Chemistry
TA serves as the water’s primary buffering agent, meaning it resists fluctuations in the pH level. This buffering capacity is achieved by bicarbonates neutralizing acids introduced from external sources. These sources often include acidic rain, swimmer perspiration, and the off-gassing of carbon dioxide. Without sufficient alkalinity, the water cannot absorb these acidic inputs, leading to rapid changes in pH that make chemical management nearly impossible.
The ideal concentration range for Total Alkalinity in most swimming pools is between 80 and 120 parts per million (ppm). This range provides the stability needed to keep the pH balanced, preventing it from drifting rapidly. Low TA means the water lacks adequate buffering capacity, causing the pH to swing wildly in response to factors like rain or the addition of sanitizing chemicals. Extreme pH fluctuations cause discomfort for swimmers and diminish the effectiveness of chlorine sanitizers. Maintaining this buffer ensures a consistent chemical environment, which helps protect pool surfaces and equipment from corrosion or scale formation.
Identifying Low Alkalinity and Necessary Testing
Identifying low alkalinity begins with accurate and consistent water testing using specialized kits. These tools range from simple test strips to precise liquid reagent kits or advanced digital testers. Pool owners should collect a water sample from elbow depth, away from skimmers or return lines, to represent the average water chemistry. TA must be measured and adjusted before attempting to correct the pH level.
Low TA is often indicated by a persistent inability to maintain a stable pH reading, even after repeated adjustments. Common causes contributing to low TA include frequent dosing with acidic chemicals, such as liquid chlorine or muriatic acid, and the introduction of large volumes of naturally acidic rainwater. Addressing alkalinity first establishes the necessary chemical foundation. Correcting pH before TA is fixed often results in temporary stability, leading to continuous chemical adjustments as the pH rapidly drifts again.
Step-by-Step Guide to Raising Alkalinity
The standard chemical used to raise Total Alkalinity is sodium bicarbonate, commonly known as baking soda, which is frequently marketed as “Alkalinity Increaser” for pools. This compound introduces bicarbonate ions into the water, increasing the concentration of the buffering agents. Before adding any chemical, calculate the required dosage based on the pool’s volume and the amount of increase needed to reach the target 80–120 ppm range.
A guideline suggests that adding approximately 1.5 pounds of sodium bicarbonate per 10,000 gallons of water will raise the TA level by about 10 ppm. This specific ratio allows pool owners to precisely determine the mass of chemical needed. Handling the chemical requires caution; protective eyewear and gloves should be worn during the mixing process and application.
The application procedure involves pre-diluting the calculated amount of sodium bicarbonate in a large bucket of pool water until it is fully dissolved. This prevents the powder from settling on the pool floor, which could lead to localized high concentrations that might stain the surface. With the circulation pump running, the dissolved solution should be slowly poured into the deep end or gradually dispersed around the perimeter.
This method ensures the chemical is rapidly dispersed throughout the water, promoting uniform adjustment. After the addition, the pump must run for at least 6 to 8 hours, which typically equates to one full water turnover cycle. This extended circulation time guarantees the new alkalinity level is thoroughly mixed and stabilized before retesting. Retesting the TA level confirms the adjustment was successful and provides the baseline for balancing the water chemistry.
Managing pH Stability After Adjustment
Raising the Total Alkalinity by adding sodium bicarbonate results in a simultaneous increase in the pool’s pH level. This occurs because the added bicarbonate ions contribute to the overall alkalinity, often pushing the pH above the ideal range of 7.4 to 7.6. The adjustment of TA is not the final step in balancing the water chemistry; it is the necessary precursor to correcting the pH.
Once the TA has been stabilized in the target range, the focus shifts to reducing the pH. This is accomplished by adding an acidic compound, such as muriatic acid or sodium bisulfate (dry acid). Adjusting the TA first allows the water to gain the necessary buffering capacity, enabling the pH to be brought into the correct range and remain there consistently. This sequence is fundamental to maintaining long-term chemical stability and preventing erratic pH swings.