Bog Filter Sizing Calculator

Designing a clear, low-maintenance pond starts here.

Use this free calculator to figure out how big your bog filter should be — and what size pump to use.

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🧠 What You’ll Need to Input:

1. Your pond’s volume (in litres or gallons — you can toggle units)
2. The % of your pond volume to dedicate to a bog filter:
   Here’s a quick guide:
   • 5% – Wildlife pond
   • 10% – Goldfish/small fish pond
   • 15–20% – Koi pond or large fish
   • 25%+ – Ducks, turtles, or heavy waste loads

This calculator shows you the empty space needed in your bog — that’s the size of the rock and media zone where good bacteria do their thing.

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Pump Sizing Calculator

Now that you know your filter size, let’s choose the right pump.

This tool calculates the maximum recommended flow rate (litres or gallons per hour).
I prefer variable speed pumps so I can dial it back and save on power.

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📘 Want the Full System?

These calculators give you a great starting point — but building a clear, low-maintenance pond takes more than just two numbers.

Inside my interactive formulas guide, I’ll show you everything I use to design ponds that are simple to maintain and beautiful to look at.

📘You’ll learn:

• How to place your pump so it doesn’t clog
• Fast ways to estimate volume (even with weird pond shapes)
• Bog designs that are easy to clean and look great
• How to arrange rocks so they look natural, not dumped in
• Waterfall and stream planning tips
• Common design mistakes that cost DIYers time and money

💰 This guide has the potential to save you thousands — seriously.
No need for overpriced filter systems or endless trial and error.
I’ve personally saved at least $15,000 on components using this exact system in my own ponds.

🙌 Who’s It For?

✅ DIYers who want a real plan (without Googling every step)
✅ Anyone thinking about a bog filter and wants to do it right
✅ Pond owners sick of filters that don’t work
✅ Builders who want natural water quality without chemicals
✅ People who want their pond to just work

📘 You’ll also get:

✅ Access to a private community — share photos, videos, ask questions
✅ Your very own KevBot — my AI assistant trained on all my pond knowledge
✅  Pond Ecology Basics — understand how your pond really works
✅ Free updates, exclusive tips, and future tools as they’re released

These tools have helped people all over the world design better ponds — without breaking the bank. I think you’ll love it.

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💬 What Others Are Saying

Real success stories from around the world:

✅ Christopher (Oregon, USA) built a pond for his ducks and koi. “Dear Kev, I will never stop thanking you! Infinite thanks!”

✅ Brad (Perth, Australia) created a huge pond packed with fish. “Hi Kev, I did the work, but I couldn’t have done it without your information and I will be eternally grateful. Everyone that asks me about my pond I send them straight to your channel, ozponds.”

✅ Tom (Warsaw, Poland) built a beautiful, self-sustaining pond in the heart of the city. “Dear Kev, Thanks to your detailed instructions and practical advice, I was able to build my own pond, which has exceeded my wildest expectations.”

✅ Stephanie & Nick (Santa Cruz, USA) retrofitted their existing pond using the blueprint: “For years, our 9′ x 3′ x 3′ pond with koi and goldfish had cloudy water. 

We tried everything—pumps, aerators, chemicals—nothing worked! Then we found your channel, got your guide, and built a bog filter. 

One month later, the water is crystal clear! We may tweak the flow rate, but the results are amazing. THANK YOU from Santa Cruz!”

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💬 Every day, I hear from people who used to struggle with their ponds—now they spend less time maintaining and more time enjoying their clean, healthy water.

This system just works, Use the guide to build or transform your pond—permanently.

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