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Pool Salt Calculator

Determine exactly how many pounds of salt to add to reach your target PPM.

Most salt systems prefer 2700 – 3400 PPM.
Amount of salt to add:
0 lbs
(approx. 0 bags)
0 kg
function calculatePoolSalt() { var volume = parseFloat(document.getElementById('poolVolume').value); var current = parseFloat(document.getElementById('currentSalt').value); var target = parseFloat(document.getElementById('targetSalt').value); var resultWrapper = document.getElementById('saltResultWrapper'); if (isNaN(volume) || isNaN(current) || isNaN(target) || volume <= 0) { alert("Please enter valid numbers for all fields."); return; } var ppmDifference = target – current; if (ppmDifference <= 0) { document.getElementById('saltLbs').innerText = "0 lbs"; document.getElementById('saltBags').innerText = "Your salt level is already at or above target."; document.getElementById('saltKg').innerText = "0 kg"; } else { // Standard formula: Lbs of Salt = (Target PPM – Current PPM) * 0.00000834 * Gallons var lbsNeeded = ppmDifference * 0.0000083454 * volume; var kgNeeded = lbsNeeded * 0.453592; var bagsNeeded = Math.ceil(lbsNeeded / 40); // Assuming 40lb bags document.getElementById('saltLbs').innerText = lbsNeeded.toFixed(1) + " lbs"; document.getElementById('saltBags').innerText = "Approximately " + bagsNeeded + " bags (40 lbs each)"; document.getElementById('saltKg').innerText = kgNeeded.toFixed(1) + " kg"; } resultWrapper.style.display = 'block'; }

How to Use the Pool Salt Calculator

Maintaining the correct salinity level is critical for the performance of your Salt Chlorine Generator (SCG). If salt levels are too low, the cell cannot produce enough chlorine to keep the water sanitized. If levels are too high, you risk corrosion of pool equipment and the "salty taste" commonly associated with seawater. This calculator helps you pinpoint the exact amount of salt needed to reach your manufacturer's recommended levels.

Why Salt Levels Matter

Most salt water pools are designed to operate between 2,700 and 3,400 parts per million (PPM), with 3,200 PPM being the industry "sweet spot." Unlike other chemicals that evaporate or dissipate, salt only leaves your pool through splash-out, backwashing, or leaks. This means you typically only need to "top off" your salt levels at the start of the season or after heavy rain.

Step-By-Step Guide to Adding Salt

  1. Test Your Water: Never guess your current salt level. Use a reliable digital salt meter or salt test strips to get an accurate PPM reading.
  2. Calculate Your Volume: You must know how many gallons of water your pool holds. (Length x Width x Average Depth x 7.5).
  3. Input the Data: Enter your current PPM and your desired target PPM (check your salt cell manual for its specific ideal range) into the calculator above.
  4. Buy Pool Grade Salt: Only use 99.8% pure non-iodized salt specifically labeled for swimming pools. Avoid rock salt or table salt, which contain additives that can stain your liner.
  5. Add and Circulate: Pour the salt around the perimeter of the deep end. Brush the salt until it is fully dissolved to prevent staining. Keep the pump running for 24 hours after adding.
Expert Tip: Always turn your salt chlorine generator OFF before adding salt. Wait until the salt is completely dissolved (usually 24 hours) before turning the generator back on to prevent "high salt" error codes that can damage the internal electronics.

Realistic Calculation Example

Imagine you have a 20,000-gallon pool. Your current test shows 2,200 PPM, and your generator manual recommends 3,200 PPM.

  • PPM Increase Needed: 1,000 PPM
  • Formula: 1,000 (PPM) x 20,000 (Gallons) x 0.00000834
  • Result: 166.8 lbs of salt.
  • Bags: You would need roughly 4.2 bags (40 lbs each). In this case, adding 4 bags and re-testing the next day is the safest approach.

Frequently Asked Questions

Can I use too much salt?

Yes. If your salt level exceeds 4,500 PPM, most salt systems will shut down to protect the power center. The only way to lower salt levels is to partially drain the pool and refill it with fresh water.

How long does it take for salt to dissolve?

With proper brushing and circulation, pool salt typically dissolves in 1 to 4 hours. However, you should wait 24 hours before re-testing or turning on the salt cell to ensure the water is perfectly homogenous.

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