Bog Filter Sizing Calculator

This calculator can be used to help you determine the size of your bog filter.

You are required to input your ponds volume. If you are unsure how to calculate the volume of your pond- go here.

You will also need to input the % of the pond volume that will be a bog filter. This is determined by the use of the pond. For example:

• A wildlife pond enter 5
• Fish pond (goldfish or other small fish) enter 10
• Koi pond (or other large fish) enter 15 or 20 (more filtration is always better)
• A pond for swimming or where you want to achieve the best water quality enter 25 or more

You can toggle the calculator between litres and gallons, whichever you use in your country.

The calculator will tell you how many litres or gallons your bog needs to hold, this is empty space, not water. The filter is filled with rock and pebble or other filter media and then water is pumped through. Therefore the size of the filter is really the amount of media available for good bacteria to colonise. I hope that makes sense.

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Now that you know the size of the filter you can also use the calculator below to calculate the size of the pump. I like to use variable speed pumps so that I can dial the pump back and save on energy costs.

The calculator below will give you the maximum output ( litres or gallons per hour, again use the toggle to choose what measure of volume is used in your country). This is the pump size you would buy, you can then experiment with how low a flow you can use and still achieve great results.

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I hope these free resources have helped you. If you want to create something truly awesome you might like to buy my pond building formulas pdf. This has lots of useful information that I use when I'm designing my ponds.

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And don't forget to sign up for my mailing list, I'm not into spam just helping people build and maintain their ponds without spending a fortune.

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