Starter, maintenance and sludge bacteria

 🧬 How bacteria work
1️⃣ Starter bacteria

They are used when setting up a pond or after cleaning the filter.

Their task is to quickly colonize the biological filtration in order to establish a stable nitrogen cycle.

They transform harmful substances (ammonia, nitrites) into less harmful ones (nitrates) through nitrification processes.

Without them, toxic ammonia and nitrites would quickly increase in the pond, which endangers the fish.

2️⃣ Maintenance bacteria

They are used regularly during the season.

They promote the decomposition of organic waste (leaves, feces, food residues).

They help maintain clean and transparent water and the balance of the biological filter.

3️⃣ Sludge bacteria

Specialized bacteria for the decomposition of sediments on the bottom of the pond and filter sludge.

They reduce the volume of sludge and odor.

They help prevent anoxic zones where harmful substances would form.

🌱 Bacterial requirements

In order for bacteria to function optimally, they need:

Water temperature – most nitrifying bacteria work optimally at 15–25°C.

Water oxygenation – sufficient oxygen is essential for aerobic bacteria.

Correct pH – most bacteria prefer a pH of 6.5–8.0.

Nutrient availability – ammonia, nitrites, organic residues are their "food".

Biological surface – bacteria stay on filters, biofilms, biostones.

🩺 Impact on pond health
👍 Benefits

Reduce toxic substances (ammonia, nitrites).

Promote healthy filter microflora.

Reduce sludge odor.

They help prevent algae blooms thanks to a balanced biological balance.

👎 Disadvantages (if used incorrectly)

If the dosage is exceeded, they can temporarily increase turbidity.

If there is a lack of oxygen, they can die, which causes a sharp increase in organic matter and odor.

Improper storage (heat, frost) can cause loss of effectiveness.

⚠️ Common problems

Insufficient bacterial activity

Cause: low temperature, lack of oxygen, too much organic waste

Solution: adding new bacteria, aeration, checking the filter

Sludge odor

Cause: anaerobic conditions, lack of sludge bacteria

Solution: sludge bacteria, bottom aeration

Rapid algae growth

Cause: nutrient imbalance, few maintenance bacteria

Solution: regular dosing of maintenance bacteria, mechanical cleaning, UV sterilization

🧪 Types of bacteria for ponds

Nitrifying bacteria – starter, operating

Nitrosomonas (ammonia → nitrites)

Nitrobacter (nitrites → nitrates)

Organic-decomposing bacteria – maintenance

Bacillus spp., Pseudomonas spp.

Sludge-decomposing bacteria - sludge

Anaerobic and microaerophilic species that tolerate low oxygen

🛠️ Advantages and disadvantages of using bacteria
Type of bacteria Advantages Disadvantages
Starter Quick setup of the biological filter Requires a temperature of >10°C
Maintenance Stabilizes the biological balance Must be replenished regularly
Sludge Reduces the amount of sludge and odor Slower effects, dependent on flow and oxygen

🧠 How to choose the right bacteria

Pond size and number of fish

Larger ponds or ponds with koi → more bacteria

Purpose of use

Starter: for a new pond or after a major cleaning

Maintenance: throughout the season

Sludge: if you have a problem with sludge on the bottom

Form

Powder, granules or liquid concentrates

Liquids have a faster onset of action

Storage

Keep refrigerated and protect from direct sunlight

Biological compatibility

Choose bacteria specific to freshwater ponds

📌 Practical recommendations for ponds

New pond: use starter bacteria when filling and turning on the filter

Seasonal maintenance: maintenance bacteria every 2-4 weeks

Sludge problems: supplement sludge bacteria during warm water periods

After heavy feeding or large water changes: temporarily increase the dosage of maintenance bacteria

Monitoring: check ammonia, nitrite and nitrate

🟢 Summary

Bacteria are key to a healthy pond.

Starter bacteria set up the nitrogen cycle.

Maintenance bacteria stabilize the water and filtration.

Sludge bacteria reduce sediment and odor.

Proper use of bacteria means better water quality, less algae and healthier fish.