Bead filters for garden ponds

⚙️ HOW BEAD FILTERS WORK
1️⃣ Mechanical filtration

Water from the pond passes through a mechanical pre-filter, which captures larger impurities such as leaves, manure and food residues.

This prevents the bead filter itself from clogging.

2️⃣ Biological filtration

Beads provide an extremely large surface area for nitrifying bacteria, which convert:

ammonia → nitrites → nitrates

The filter allows for a high biological capacity, which is ideal for ponds with a large number of fish (Koi).

3️⃣ Self-cleaning principle

Bead filters usually have a rotating or reversing mechanism that removes the trapped impurities from the beads during cleaning and flushes them into the waste.

This makes maintenance easier and the biological medium remains active, which preserves the nitrifying bacteria.

4️⃣ Pressure operation

Bead filters are pressure operated - water flows into them under pressure, which allows:

connection to waterfalls and fountains

high flow volume

compact placement outside the pond

🏠 REQUIREMENTS OF BEAD FILTERS
💧 Water

Suitable for larger Koi ponds where there is a high density of fish

Water temperature: approx. 5–30 °C, optimal biological activity at 15–25 °C

⚙️ Maintenance

Regular start of the self-cleaning cycle

Occasional cleaning of the mechanical pre-filter

The biological medium (beads) usually does not require cleaning with chemicals

🌞 Location

Can be next to the pond or below the level

It is resistant to UV radiation and weather conditions, but may require frost protection in winter

🧠 "NATURE" OF BEAD FILTERS

Highly efficient, stable and reliable system for Koi and ponds with high load

Easy to maintain manually compared to chamber filters

Sensitive to incorrect sizing - an undersized filter will not keep the water clean

🧱 TYPES OF BEAD FILTERS
1️⃣ Pressure bead filters with manual cleaning

Require manual rinsing of the beads

Lower price, suitable for smaller to medium ponds

2️⃣ Self-cleaning bead filters

Have a rotating or reverse flow that automatically removes trapped dirt

Ideal for medium and large Koi ponds with high fish density

3️⃣ Combined bead filters with UV sterilizer

Integrated UV-C sterilizer reduces the occurrence of algae and pathogens

Beneficial for bright sunny conditions and algae problems

🩺 IMPACT ON POND HEALTH
POSITIVE

✔️ very clean and transparent water
✔️ stable ammonia level and nitrites
✔️ healthy fish, less stress and disease
✔️ reduced occurrence of algae and pathogens (for UV versions)

NEGATIVE / FREQUENT PROBLEMS

❌ clogging of the mechanical pre-filter → reduced flow rate
❌ incorrect sizing → filter overload
❌ frost and extreme weather → risk of damage
❌ inappropriate installation – reduced efficiency of biological filtration

⚖️ ADVANTAGES AND DISADVANTAGES
👍 ADVANTAGES

✅ high biological capacity
✅ self-cleaning or simple manual system
✅ stable water quality even with a large number of fish
✅ possibility of integrating a UV sterilizer
✅ compact and aesthetic placement outside the pond

👎 DISADVANTAGES

❌ higher initial investment
❌ requires regular flushing of the mechanical pre-filter
❌ sensitive to undersizing
❌ external filters require protection against frost

🛒 HOW TO CHOOSE THE RIGHT ONE

Pond size and number of fish – the bead filter must be sized for water volume and biological load

Filter type – manual or self-cleaning

UV sterilization – suitable for higher solar radiation and algae problems

Maintenance – consider whether you want manual cleaning or an automatic cycle

Quality and material – UV, corrosion and frost resistance

📌 Tip: bead filters are ideal for ponds over 5 m³ with a large number of Koi, where the goal is stable biological filtration and clear water with minimal maintenance.

🧭 PRACTICAL TIPS

When cleaning the mechanical pre-filter, do not neglect the waste so that the bead filter does not clog

Choose a filter with a flow reserve so that the efficiency does not decrease under higher loads

Protect the filter from frost in winter and excessive UV radiation

When using a UV sterilizer, check the lamp performance and clean it regularly

📌 SUMMARY

Bead filters are the best solution for Koi ponds and larger garden ponds, where high biological capacity and clean, transparent water are required.

High efficiency of mechanical and biological filtration

Stable water quality with a high number of fish

Minimal maintenance while maintaining nitrifying bacteria

Compact, robust and flexible solution