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PUREFLOW BIO / ENGINEERING FIELD GUIDE

How to Size a Drum FilterFlow, Solids Load and Mesh

Work out the right drum filter size from your flow rate, daily feed, mesh choice and installation space, with a short worked example.

Explore the process ↗Open the workbench
7 MIN GUIDEUPDATED NOVEMBER 2026
Reference illustration for How to Size a Drum Filter: Flow, Solids Load and MeshEQUIPMENT REFERENCE
Equipment reference illustration. Confirm the supplied model configuration and installation arrangement from its approved documentation.
01Understand the mechanismInspect the relevant process stages.
02Review the operating dutyKeep assumptions and measured values visible.
03Prepare the next decisionUse the guide, tools and project checks.
INTERACTIVE PROCESS ATLAS

See the mechanism.
Understand the duty.

Select a route or a stage to inspect the process. The cutaway explains the equipment and water environment; it is a teaching illustration, not a project drawing.

Swipe horizontally to inspect the equipment. Stage buttons below also centre the selected component.
Rotary drum screen and separate waste routePUREFLOW / INTERACTIVE PROCESS ATLASCONCEPT LAYOUT · NOT TO SCALECULTURE WATERSCREEN + SPRAY + DRIVEDOWNSTREAM BIOLOGYWASH WASTE OUTWASH SUPPLYMotion explains the process; it is not a measured flow rate or biological time model.
Follow water across the screen and toward the downstream treatment. The line speed is illustrative.
Selected process stage

Capture solids

Use actual flow, screen opening and solids duty.

How it works

Particles are retained as water crosses the screen. Dissolved contaminants require other treatment stages.

What to establish
  • Use actual flow, screen opening and solids duty.
  • Confirm approved levels, wash supply and waste drainage.
  • Observe a complete guarded cycle before changing settings.

Continue this guide ↗

Filtration mode. Wash sequence and timing are illustrative. Geometry, stage order, pipe routes and equipment configuration are conceptual. Use the approved project design, operating instructions and verified model data.

Key takeaways

  • Start with flow: Add up the water that will actually pass the filter, in m³/h.
  • Then the solids: In a fish farm the solids come from feed.
  • Choose the mesh: A finer mesh clogs sooner, so a fine mesh effectively lowers the flow a given drum can handle.
  • Leave headroom: Peaks happen: a feeding bout, a pump surge, a tank flush.
Reference illustration for How to Size a Drum Filter: Flow, Solids Load and Mesh
Equipment reference visual; not evidence of a completed installation.
THE SHORT ANSWER

Start with flow

Add up the water that will actually pass the filter, in m³/h. For a fish tank, use the turnover you plan for. If you are unsure, the turnover rate guide shows how to get there.

How to Size a Drum Filter - Pureflow Bio
Reference visual. Equipment configuration and project details must be confirmed separately.
DRUM FILTERS

Then the solids

In a fish farm the solids come from feed. As a rough guide, a quarter to a third of the feed you add ends up as solids, depending on the feed and species. More feed means a heavier load, and a heavier load means the filter washes more often. If the filter is only just big enough, it will wash non-stop.

PLANNING WORKBENCH

Work with your own numbers.

Use the tools below to explore the relevant arithmetic. Enter measured values or declared assumptions. An estimate does not establish equipment capacity, biological performance or a safe operating limit.

Flow & turnover planner

Relate a measured water volume to a selected turnover time. Confirm the time from the application and hydraulic design.

Assumptions and limits

A planning allowance is your assumption. This calculation does not choose a filter, prove treatment capacity or account for pump head.

—Base flow · m³/h
—Planning flow · m³/h
—Planning flow · L/h
Enter your values, or load the labelled arithmetic example. No design values are pre-filled.
FormulaFlow = volume ÷ turnover time. Planning flow = flow × (1 + allowance ÷ 100).
Convert units before you calculate
Choose units and enter a value.

Planning arithmetic · inputs remain visible for review · example values are not operating recommendations

DRUM FILTERS

Choose the mesh

A finer mesh clogs sooner, so a fine mesh effectively lowers the flow a given drum can handle. Pick the mesh first, then check the flow rating at that mesh. See mesh size.

DRUM FILTERS

Leave headroom

Peaks happen: a feeding bout, a pump surge, a tank flush. Choose a model rated comfortably above your normal flow, so peaks do not make the water spill over the top.

DRUM FILTERS

Check the room

You need space for the filter, its drain, service access and often a collection tank for sludge. Measure the head available between tank outlet and filter inlet if you want gravity feeding.

DRUM FILTERS

A quick example

A recirculating tank loop of 30 m³/h with a fine mesh and heavy feeding might call for a filter rated well above 30 m³/h, not exactly at it. Bring us your numbers and we will check them against our RDF range.

Pureflow Bio equipment for this

Standard drum filters (RDF) →Automatic solids removal.Pro drum filters →Compact pump-fed drum filters.
PROJECT REVIEW

Confirm the hydraulic duty

Use these questions to prepare a project brief or an operating review. Check an item only when the information has been recorded for your installation.

0 of 3 checked

This checklist is a working aid in the current page session, not a saved maintenance record.

QUESTIONS

How to Size a Drum Filter FAQ

Can I size a drum filter from tank volume?

Not reliably. Flow, feed and mesh are better inputs than volume.

What if I am between two sizes?

Go up. A slightly larger filter washes less often and copes with peaks.

KEEP READING
Our standard drum filters (RDF)→Drum filter mesh size→Turnover rate→Drum Filter Installation Checklist: Levels, Drains and Power ↗Drum Filter Maintenance Schedule: Daily to Yearly ↗

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