PangPang ToolsTank liquid volume: 20 m³; circulation flow: 5 m³/h
4 h per theoretical turnover; 6 turnovers/day; 83.333333 L/min20 ÷ 5 = 4 hours. At constant flow, 24 ÷ 4 gives six equivalent tank volumes per day; it does not mean all water has mixed six times.
Construction & Electrical
Water tank turnover time calculator
About this tool
Use this calculator to compare a tank's current water volume with the circulation or replacement flow rate. Turnover time is liquid volume (m³) divided by flow (m³/h); the result is in hours. The additional results convert that flow to litres per minute and calculate how many theoretical turnovers fit in 24 hours. This is a hydraulic volume calculation, not evidence that every part of the tank mixes or that water has been disinfected.
Tank filling & circulation time
Choose a task. Inputs stay in this page only.
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Result
Worked examples
Tank liquid volume: 9 m³; circulation flow: 4.5 m³/h
2 h per theoretical turnover; 12 turnovers/day; 75 L/minHalving the volume-to-flow ratio halves the theoretical exchange time. Actual residence-time distribution can still be uneven.
Questions & answers
Does one tank turnover mean all the water has been replaced?
No. It means an amount equal to the stated tank volume has flowed through. Mixing patterns, inlet and outlet positions, and stagnant zones can leave some water much longer.
Should I use rated pump capacity or measured flow?
Use the verified flow through the tank if available. Pipe friction, valves and operating conditions can reduce actual flow below the pump's headline capacity.
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Result
Worked examples
Target tank volume (m³): 20, Current volume (m³): 5, Pump inflow (m³/h): 8, Simultaneous outflow (m³/h): 1
Remaining volume: 15 m³Using these sample input values gives the first labelled output above. Assumes constant net inflow, independent of pump head, pressure and startup.
Questions & answers
Can I use the default numbers for purchasing or safety certification?
No. Replace the examples with your real values. Assumes constant net inflow, independent of pump head, pressure and startup.