Fungicides and Biocides in Diesel Fuel

Microbial growth in diesel fuel is often called diesel bug. It is commonly described as algae, but the problem usually involves bacteria, fungi, or other microbes that grow where water and fuel meet.

Why Water Matters

Microbes need water to grow. If a tank has water at the bottom, the fuel/water interface can become a place for microbial growth. This can lead to slime, sediment, plugged filters, corrosion, and fuel quality problems.

What a Biocide Does

A diesel biocide is designed to kill microbial contamination. It can be useful when contamination is present, but it is not a substitute for good tank maintenance. Dead microbes and debris may still need to be filtered or removed.

Prevention

• Keep fuel tanks clean and dry.
• Drain water when needed.
• Use proper filtration.
• Inspect stored fuel regularly.
• Use stabilizer and treatment products appropriate for the storage situation.

Need help choosing? Start with Opti-Lube diesel fuel additives or review our FAQ for dosing, storage, and compatibility questions.