Pool Turnover Rate Calculator
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Turnover Time:
–
Cycles Per 24 Hours:
–
Gallons Per Hour:
–
Required Flow Rates for Gallon Pool
| Target Turnover Time |
Required Flow Rate (GPM) |
Understanding Pool Turnover Rate
The pool turnover rate is the amount of time it takes for your pool pump to circulate the entire volume of water in your swimming pool through the filtration system exactly once. Maintaining an appropriate turnover rate is critical for keeping water clean, clear, and chemically balanced.
The Golden Rule: Most residential swimming pools should aim for a turnover rate of 8 to 12 hours. Ideally, the water should pass through the filter at least 2 to 3 times (cycles) within a 24-hour period.
Why Turnover Rate Matters
If your turnover rate is too slow (taking too long to filter all the water), you risk:
- Algae Growth: Stagnant water creates a breeding ground for algae.
- Cloudy Water: Fine debris and particulates remain suspended in the water rather than being trapped by the filter.
- Chemical Imbalance: Chlorine and other chemicals are not distributed evenly throughout the pool, leaving "dead spots."
How to Calculate Pool Turnover
To calculate the turnover rate, you need two key numbers: the Volume of the pool (in gallons) and the Flow Rate of your pump (in Gallons Per Minute or GPM).
1. Calculate Turnover Time (Hours)
This formula tells you how many hours it takes to filter the whole pool once.
Formula: Pool Volume ÷ (Flow Rate × 60) = Turnover Hours
Example: For a 24,000-gallon pool with a pump running at 60 GPM:
- 60 GPM × 60 minutes = 3,600 Gallons Per Hour (GPH)
- 24,000 Gallons ÷ 3,600 GPH = 6.67 Hours
2. Calculate Required Flow Rate (GPM)
If you know your pool volume and have a target turnover time (e.g., 8 hours), you can calculate the pump size (GPM) needed.
Formula: Pool Volume ÷ (Target Hours × 60) = Required GPM
Example: You have a 15,000-gallon pool and want an 8-hour turnover:
- 8 Hours × 60 minutes = 480 minutes
- 15,000 Gallons ÷ 480 minutes = 31.25 GPM
Turnover Guidelines by Pool Type
Different types of pools have different requirements based on usage load and regulations:
| Pool Type |
Recommended Turnover Time |
| Residential Pools |
8 – 12 Hours |
| Semi-Commercial / Condos |
6 – 8 Hours |
| Commercial / Public Pools |
4 – 6 Hours (Often regulated by state) |
| Spas / Hot Tubs |
20 – 30 Minutes |
| Wading Pools |
1 – 2 Hours |
Adjusting Variable Speed Pumps
If you own a variable speed pump, this calculator is incredibly useful. You can run the pump at a lower RPM (lower GPM) for a longer period to save electricity while still achieving the required turnover cycles. For example, running at 40 GPM for 12 hours is often more energy-efficient than running at 80 GPM for 6 hours.
function calculatePoolTurnover() {
var volumeInput = document.getElementById('poolVolume');
var flowRateInput = document.getElementById('flowRate');
var volume = parseFloat(volumeInput.value);
var flowRate = parseFloat(flowRateInput.value);
// Validation
if (isNaN(volume) || volume <= 0) {
alert("Please enter a valid pool volume.");
return;
}
if (isNaN(flowRate) || flowRate 12) {
statusText = "Warning: Turnover is too slow (>12h). Consider increasing pump speed or running longer.";
statusClass = "ptr-status-bad";
} else if (turnoverTimeHours = 6) {
statusText = "Excellent: Turnover rate is within the ideal residential range (6-12h).";
statusClass = "ptr-status-good";
} else {
statusText = "Fast: Turnover is very quick (<6h). Efficient, but potentially using excess energy.";
statusClass = "ptr-status-good";
}
statusDiv.className = "ptr-status " + statusClass;
statusDiv.innerHTML = statusText;
// Generate Reference Table for different timeframes
generateReferenceTable(volume);
}
function generateReferenceTable(volume) {
var tableContainer = document.getElementById('referenceTable');
var tableBody = document.getElementById('referenceTableBody');
var volumeDisplay = document.getElementById('tableVolumeDisplay');
volumeDisplay.innerHTML = volume.toLocaleString();
tableBody.innerHTML = ""; // Clear previous
var targetTimes = [4, 6, 8, 10, 12, 24];
for (var i = 0; i < targetTimes.length; i++) {
var hours = targetTimes[i];
// Formula: Volume / (Hours * 60) = GPM
var requiredGPM = volume / (hours * 60);
var row = "
" +
"| " + hours + " Hours | " +
"" + requiredGPM.toFixed(1) + " GPM | " +
"
";
tableBody.innerHTML += row;
}
tableContainer.style.display = "block";
}