100 ppm (Ideal for most pools)
120 ppm (Slightly higher, good for saltwater)
80 ppm (Lower end, may need adjustment)
140 ppm (Higher end, common target)
Your recommended dosage will appear here.
Understanding Pool Total Alkalinity
Total Alkalinity (TA) is a crucial water chemistry parameter for swimming pools. It acts as a buffer, stabilizing the pH level of your pool water. Without proper TA, your pH can fluctuate dramatically, leading to a host of problems.
Why is Total Alkalinity Important?
pH Stability: TA prevents rapid swings in pH, ensuring it remains within the ideal range (typically 7.2-7.6). Unstable pH can cause discomfort to swimmers, damage pool equipment, and reduce the effectiveness of sanitizers like chlorine.
Corrosion Prevention: Low TA can lead to corrosive water, which can damage pool surfaces (plaster, vinyl liners), metal components (ladders, heaters), and grout.
Scale Formation: High TA can contribute to scale formation on pool surfaces and equipment.
Sanitizer Efficacy: Chlorine, the most common pool sanitizer, works most effectively within a specific pH range, which TA helps maintain.
Ideal Total Alkalinity Levels
The generally accepted ideal range for Total Alkalinity in most swimming pools is between 80 ppm (parts per million) and 120 ppm. Some sources suggest slightly different ranges, but this is a widely recommended target.
How the Alkalinity Calculator Works
This calculator helps you determine the amount of a pH increaser (typically sodium bicarbonate, also known as baking soda) or a pH decreaser (typically muriatic acid or sodium bisulfate) you might need to adjust your pool's Total Alkalinity.
The calculation is based on standard dosage rates for common pool chemicals. The formula generally used is:
Dosage (in lbs or fluid oz) = (Target TA – Current TA) * Adjustment Factor * Pool Volume
The "Adjustment Factor" varies depending on the chemical used and is simplified in this calculator's logic to provide a practical estimate. For raising alkalinity, sodium bicarbonate is commonly used. For lowering alkalinity, acid is used.
Note: This calculator provides an estimated dosage. Always follow the manufacturer's instructions on the chemical product packaging and test your water again after adding chemicals to confirm the levels are correct. The exact amount of chemical needed can vary based on water conditions, existing stabilizer levels, and the specific product used.
Common Pool Chemicals for Alkalinity Adjustment
To Increase Alkalinity: Sodium Bicarbonate (Baking Soda)
To Decrease Alkalinity: Muriatic Acid (liquid) or Sodium Bisulfate (dry acid)
This calculator focuses on estimating the amount of product needed to reach your target. If your current TA is significantly higher than your target, you will likely need to use an acid to lower it, which will also tend to lower pH. If your TA is lower than your target, you will add sodium bicarbonate to raise it, which will also tend to raise pH slightly.
function calculateAlkalinity() {
var poolVolume = parseFloat(document.getElementById("poolVolume").value);
var currentAlkalinity = parseFloat(document.getElementById("currentAlkalinity").value);
var targetAlkalinity = parseFloat(document.getElementById("targetAlkalinity").value);
var resultDiv = document.getElementById("result");
// Clear previous classes
resultDiv.className = "";
// Input validation
if (isNaN(poolVolume) || poolVolume <= 0) {
resultDiv.textContent = "Please enter a valid pool volume.";
return;
}
if (isNaN(currentAlkalinity) || currentAlkalinity < 0) {
resultDiv.textContent = "Please enter a valid current alkalinity level.";
return;
}
if (isNaN(targetAlkalinity) || targetAlkalinity 0) {
// Calculate dosage to INCREASE alkalinity using Sodium Bicarbonate (Baking Soda)
// Approximate: 1.25 lbs per 10,000 gallons to raise TA by 10 ppm
var lbsPer10000GallonsPer10PPM = 1.25;
dosage = (alkalinityDifference / 10) * lbsPer10000GallonsPer10PPM * (poolVolume / 10000);
resultDiv.textContent = "Add approximately " + dosage.toFixed(2) + " lbs of Sodium Bicarbonate (Baking Soda).";
if (dosage 5) {
resultDiv.classList.add("high"); // Indicate a large amount needed
} else {
resultDiv.classList.add("ideal"); // Indicate a moderate amount
}
} else if (alkalinityDifference < 0) {
// For lowering alkalinity, it's more complex and impacts pH.
// A simplified approach might suggest adding acid. However, it's crucial to add acid slowly and retest.
// A common rule of thumb for lowering TA with acid: 2-3 oz of Muriatic Acid per 10,000 gallons to lower TA by 10 ppm.
// This calculator will provide a warning and an estimate for acid dosage if needed.
var ozAcidPer10000GallonsPer10PPM = 2.5; // Approximation
var acidDosage = (Math.abs(alkalinityDifference) / 10) * ozAcidPer10000GallonsPer10PPM * (poolVolume / 10000);
resultDiv.textContent = "Your alkalinity is high. To lower it, add approximately " + acidDosage.toFixed(2) + " fluid oz of Muriatic Acid. Add slowly, test pH frequently, and re-test alkalinity after 24 hours.";
resultDiv.classList.add("high"); // Indicate that TA is high
} else {
resultDiv.textContent = "Your Total Alkalinity is already within the target range.";
resultDiv.classList.add("ideal");
}
}