Fuel Additives

bug1 smalldipslideSepar UK sells three varieties of fuel treatments aswell as microbial testing dipslides. Professional Fuel Testing is also available through our partner company, WASP PFS Ltd.




Bacterial infection is a major issue in fuel. There are hundreds of various bacterial infections, the two most common being “Cladosporium Resinae” (clad) and “Pseudomonas aeruginosa”.

These yeast and fungal infections cannot germinate in the fuel itself, but require the right temperature (10-40 degrees centigrade) a food source (the fuel’s hydrocarbons) and water to live. Bacterial infection most often looks like black or dark brown ‘waxy sludge’. This is often found in fuel tanks, pipes and filters. The by-product waste will then cause damage to engines.


Which treatment do I need?

This will depend on the following:-

  • the type of fuel (diesel, jet fuel etc)
  • where it is being used (on a boat, aircraft etc)
  • whether you need a biocide or biocide including improvement catalyst.

Kathon and BioKem are high performance antimicrobial agents developed to combat problems of microbial contamination and spoilage in hydrocarbon fuels. FT RED fuel treatment and improvement catalyst eliminates any fungal growth and bacterial build up, improves the fuels combustibility, cleans injectors and fuel system while improving power output.

The below table gives a good indication of which product is suitable for varying needs. If you are still unsure, please do not hesitate to This email address is being protected from spambots. You need JavaScript enabled to view it..

biocide table


Kathon FP 1.5 is a patented high performance antimicrobial agent developed specifically to combat problems of microbial contamination and spoilage in hydrocarbon fuels.


More Info




WASP Biokem SP15

WASP Biokem SP15 is a fuel micro-biocide for treatment of Cladosporium Resinae and Pseudomonas aeruginosa (the fuel bug).

More Info





WASP FTR (Fuel Treatment Red)

FTR medium

FT RED is a highly concentrated mixture of carefully formulated additives and solvents designed to easily mix with gas oils, diesel and fuel oils used for marine pleasure, ocean-going vessels, road haulage fleets, mechanical plant and agricultural units.

More Info




Fuel Testing Dip Slides for Microbial Infection

dipslidesThe Micro Dip Slides are easy to use and test for bacteria, yeast and moulds. 


More Info






On Site Fuel Testing

A comprehensive laboratory test carried out on your behalf by WASP PFS Ltd is by far the most accurate and sensible. We offer a full ISO4406 reading, percentage figures for composite parts of your fuel, as well as water content, sulphur levels, infection, etc. Our laboratory testing service then offers you a full written report, analysing your fuel and making recommendations based on your results. WASP PFS Ltd offer a comprehensive fuel testing service.






Need help selecting a filter?

See our guide to help you select the most suitable filter for your needs.

Technical Support

How it works

See how the Separ filter works to separate water and particulate from fuel. 

SWK2000 flow diagram transparancy

How to Order

Call or email us to place your order. We accept ALL major credit and debit cards, bank transfer and also PayPal. 

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Expert advice

Unsure which spare parts you require? Or if a Separ filter will meet your requirements? 

Talk to our expert team. Call 01923 276 007



Delivery options

We have a wide range of shipping options available to suit your destination and budget.



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Contact Us

3 Kingley Park, Station Road, Kings Langley, Herts, WD4 8GW

Tel: +44 (0)1923 276007

Fax: +44 (0)1923 267463

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Here to Help

Product guides

Fuel Specs


Selecting a Filter