Borax Pool Calculator

Calculate the exact amount of Borax (Sodium Tetraborate) needed for your pool

Pool Volume (Gallons)

Current Borate Level (ppm)

Target Borate Level (ppm)

Borax Price (per 76oz Box)

Calculation Results:

Why Use Borax in Your Swimming Pool?

Borax (Sodium Tetraborate Decahydrate) is a popular "secret weapon" among pool enthusiasts. It serves two primary functions: raising pH levels without drastically affecting Total Alkalinity and acting as a pH buffer when maintained at levels between 30 and 50 ppm.

1. Better pH Stability

Once you reach the recommended 30-50 ppm of borates, your pool water becomes more resistant to pH fluctuations. This is particularly helpful for pools using saltwater chlorine generators, which naturally cause pH to rise over time.

2. Algae Inhibition

While not a primary algaecide, borates act as an algaestat. This means they interfere with the metabolism of algae, making it harder for blooms to start, which can save you money on chlorine in the long run.

3. Water Clarity and "Silkiness"

Adding borates reduces the surface tension of the water. Many pool owners report that the water feels "silky" on the skin and appears visibly clearer or more "sparkling" after treatment.

How Much Borax Do I Need?

The standard dosing for 20 Mule Team Borax (the most common source) is approximately 76 ounces (4.75 lbs) per 10,000 gallons to raise borate levels by 10 parts per million (ppm).

Important Safety Note: When adding large amounts of Borax to reach 50 ppm, the pH of your pool will rise significantly. You MUST add Muriatic Acid (hydrochloric acid) simultaneously to counteract the pH rise. Use this calculator primarily to determine the dosage required for your target borate concentration.

Borax Dosage Example

If you have a 20,000-gallon pool and want to go from 0 ppm to 30 ppm borates:

Step 1: You need to raise levels by 30 ppm.
Step 2: 20,000 gallons is 2x the 10k gallon baseline.
Step 3: (76 oz * 2) * 3 = 456 ounces of Borax.
Total: Approx 28.5 lbs or six 76oz boxes.

function calculateBorax() { var volume = parseFloat(document.getElementById('poolVolume').value); var current = parseFloat(document.getElementById('currentBorates').value); var target = parseFloat(document.getElementById('targetBorates').value); var price = parseFloat(document.getElementById('boxPrice').value); var resultDiv = document.getElementById('boraxResult'); var output = document.getElementById('boraxOutput'); if (isNaN(volume) || isNaN(target) || volume <= 0) { alert("Please enter valid numbers for pool volume and target levels."); return; } if (isNaN(current)) current = 0; var ppmIncrease = target – current; if (ppmIncrease <= 0) { resultDiv.style.display = "block"; output.innerHTML = "Your current borate level is already at or above your target. No Borax addition is necessary."; return; } // Calculation: 76 oz (one standard box) raises 10,000 gallons by 10 ppm // Formula: (Target ppm Increase / 10) * (Volume / 10,000) * 76 oz var totalOunces = (ppmIncrease / 10) * (volume / 10000) * 76; var totalPounds = totalOunces / 16; var totalBoxes = totalOunces / 76; var displayText = "

Total Borax Needed: " + totalOunces.toFixed(1) + " oz
Weight in Pounds: " + totalPounds.toFixed(2) + " lbs
Standard 76oz Boxes: " + totalBoxes.toFixed(2) + " boxes
Estimated Total Cost: $" + totalCost.toFixed(2) + "

"; displayText += "*Note: Adding this amount will significantly increase pH. Be prepared to add Muriatic Acid to balance the water."; output.innerHTML = displayText; resultDiv.style.display = "block"; resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }