Sidestream Filtration Throughput

Sizes a sidestream filter so the full system volume passes through the filter at least once every turnover interval (general rule, once every 4 hours).

$$Q=\frac{V_{sys}}{t_{turnover}}$$

Variables

Symbol	Meaning	Unit
Q	required filter throughput	gal/hr or GPM
$V_{sys}$	system volume (basin plus piping plus exchangers)	gal
$t_{turnover}$	turnover target interval	hr

Worked example

System volume = 3,000 gal, turnover target = 4 hr, so throughput = 3,000 / 4 = 750 gal/hr = 12.5 GPM.

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Part of The Blueprint of Water