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Floating Fountains & Dam Aerators

Floating Fountains and Aerators for Dams, Lakes and Large Ponds

Pond Help & Information

Need a hand working out the right gear for your project? Browse our range of help pages or submit a help request directly to our specialists.

Pond Filter Flow Calculator (Manual Calculation)

Use this quick reference Pond Flow Calculator to find the ideal flow rate to keep your pond healthy when running a filter. This allows you to select the right size filter for your pond within 10-15% accuracy.

If you don't wish to use this chart to size up your filter manually, we can do it for you by submitting our online help form - click here.

Step 1 - Establish your pond volume


  • Circular Ponds
    Diameter x Diameter X Depth (meters) X 785 = Volume in litres

  • Rectangular Ponds
    Length x Width x Depth (meters)  x 1000 = Volume in litres

  • Odd shaped (Such as Kidney or rounded corners)
           Average Length x Average Width x Average Depth (meters) x 800 = Volume in litres

  • Triangular
           Length x Width x Average Depth (meters) divide by 2 x 1000 = Volume in litres

Example A rectangular pond 4 meters average length x 3 meters average width x 70cm average depth

                      Pond Volume: 4.0 x 3.0 x .7 x 1000 = 8,400 litres

Important If the sides of the pond are not vertical but tapered, reduce the volume by 10%

Step 2 - Pick your correct flow

Please make a note of your pond volume now. Now apply the pond volume to the chart below, using the fish stocking and sun situation of your pond to determine the approximate water flow required to maintain a healthy environment for your pond and it's inhabitants.

Choose the fish stocking that best suits your future fish stocking (allow a little extra for growth)

No fish No fish = Natural garden ponds with plants but no fish.
Small fish = Light fish - Natural garden pond with plants and total fish length up to 400mm* per 1,000 litres
Small fish     Small fish = Medium fish stocking - Pond with plants and total fish length of up to 800mm* per 1,000 litres
or  Light Koi/Turtles with a total length of up to 400mm*  per 1,000 litres
Fish of 3 = Heavy fish stocking with a total length up to 1000m*  per 1,000 litres
 or  Medium Koi/Turtles with a total length of 500mm*  per 1,000 litres
 Small fish
Fish of 4
= Extra Heavy fish stocking with a total length over 1000mm*  per 1,000 litres
or  Heavy Koi/Turtles with a total length of 500mm*  per 1,000 litres

*Fish when measured end to end                   Special note - The more plants the better

Armed with the pond volume and fish stocking, add the other factors, sun shade etc

       Pond in shade

Pond in partial shade 

Pond in full sun

Pond in shade

Pond in partial shade  Pond in direct sun
Or shade cloth                                                    Sun on the pond for a max of 50%  Full sun in summer all day        


Also allow for pond depth, your location and hose

If the pond is

  • less that 300mm deep add 75% to the flow 

  • between 301 & 450mm deep add 50% to the flow

  • between 451 & 600mm deep add 25% to the flow

If you live in

  • Tropical (Qld, NT or northern WA) add 35% to the flow 

  • Sub tropical (Northern NSW) add 25% to the flow 

  • Temperate (NSW, SA, VIC, Southern WA) add 15% to the flow

Hose length and diameter

If your total hose length is over 4m, or your waterfall is over 500mm, or if you have an existing hose that may be too small and can't be replaced, it may now be the time to either:

  1. Fill in one of our e-mail help forms and let us do all the calculations for you

  2. Give us a call 1800 607 388 for expert advice

Step 3 - Choose your filter

You now have the ideal flow through the filter in litres per hour for a healthy pond.

Now you need to decide what type of filter your require.

Always choose the filter first.
The horse must be ahead of the cart, so the filter must first be chosen before you can choose your pump. On each filter page there is a section named "suitable pumps"

(Remember your ideal flow through the filter will be needed)

Click one of the links below. You can sort through our range of filters very easily using a table in order to select one that suits your flow requirements.

Select your Pressure Filter

Select your Gravity Filter


Jump straight to our selection of Filter Pumps

*Please ensure you have selected your filter before you choose a pump

How we established these figures

The above quick reference calculator represent the approximate circulation required for a pond in Australia using average calculations.

When making the above calculations we have taken into account average Australian climate, average pond plants, average pond depth (on the shallow side), flow loss through a filter etc. These circumstances may vary depending on the specifics of your pond and this chart should be used as a guide only, not a guarantee.

Special note:

Please use this chart as close guide only, the only way to exactly choose a pump and filter is by using all your specific and exact factors, the above if used correctly should get you within 10 - 15% of a perfect outcome. In doubt either fill in one of our e-mail help forms or call 1800 607 388.