What is a good pond filter turnover?

General ponds: 1.5–2.0× per hour. Koi ponds: 0.5–1.0× per hour. Adjust for fish load and clarity goals.

How do you size a pond filter?

Start with required flow (volume × turnover), adjust for fish type, then size filter surface area using a media coefficient. Deeper media increases media volume.

Mechanical vs biological vs pressurized?

Mechanical filters capture debris and need moderate area; biological provide large surface area for bacteria; pressurized are compact with higher head and lower area coefficient.

No. All calculations happen in your browser. Use Export or Share Link to save.

It’s an estimate. Always confirm with supplier specs and allow 10–20% safety margin.

Pond Filter Calculator

Name: Pond Filter Calculator
Author: CalculatorBolt

Calculate pond filter size and flow rate. Enter pond volume, fish type, fish count, and media depth. Get recommended filter flow rate, surface area, and media volume. Informational only—consult suppliers. Explore more tools on free calculators on CalculatorBolt.

Calculator

Pond Volume

Units

Fish Type

Fish Count

Media Type

Media Depth

Units

Filter Flow Rate

Filter Surface Area

Media Volume

Import JSON

Turnover Rate (×/h)

Flow rounding

Area rounding

How it works

Base Flow Rate = Pond Volume × Turnover Rate. Adjust for fish load (goldfish 1.0×, koi 1.5×, mixed 1.25×). Filter Surface Area = Flow Rate × Media Coefficient (mechanical 1.5, biological 2.0, pressurized 0.5, or custom). Media Volume = Surface Area × Media Depth.

Inputs explained

Pond Volume, Fish Type (goldfish, koi, mixed), Fish Count, Media Type, Media Depth.

Example

Pond 15,000 L (15 m³), Koi, 10 fish, Biological, 30 cm depth → Base Flow = 15 × 1.0 = 15 m³/h → Adjusted = 15 × 1.5 = 22.5 m³/h → Surface Area = 22.5 × 2.0 = 45 m² → Media Volume = 45 × 0.30 = 13.5 m³ = 13,500 L.

Tips & notes

Koi produce more waste; increase flow rate for koi ponds.
Biological filters need more surface area than mechanical filters.
Include a safety margin (10–20%) when selecting a filter.

FAQs

General ponds: 1.5–2.0×/h. Koi ponds: 0.5–1.0×/h. Adjust based on fish load.

Surface Area = Flow Rate × Media Coefficient. The calculator does this automatically.

It provides an estimate. Actual filter specs may vary by manufacturer. Consult suppliers.

No. Everything runs in your browser. Use Export/Share Link to save your configuration.

Disclaimer

Informational estimate only. Actual filter requirements may vary by pond conditions and manufacturer. Consult suppliers for accurate filter selection.