We developed at "jar test" with an independent federal lab (Brookhaven National Laboratory) to test the efficacy of biocides and additives against their claims to dissolve and prevent sludge in diesel fuel.
The test consists of growing sludge in a jar of diesel fuel by introducing a little water and letting nature take its course. (takes months to get started) Once the sludge is present, we then introduce the additive at the recommended treatment ratio based on the volume of fuel present and manufacturer's recommendation.
Once a month, we remove the existing fuel and replace with fresh fuel and treat the new fuel. We repeat this process over an 18 month period.
The jar also contains a metal coupon that is evaluated for corrosion
and sludge at the end of the test.
At the end of the test, we remove the coupon and photograph it and it is scored based on the amount of sludge build up. We then wash the panel back in the fuel and strain it through a strainer and photograph the amount of sludge in the strainer.
We then assess the panel for corrosion. We have done this with 100's of additives that claim sludge and corrosion protection. We get varied results with some products performing better than others.
Algae-X is a biocide. It kills bacteria. Our study shows that biocides are effective against fungal growth but much less effective against bacterial based sludge colonies. The "glue" (exopolysaccharide) that binds these colonies together is quite resistant to biocide attack therefore, biocides are not very effective once the colonies have formed.
Biocides can also be corrosive and lose their efficacy in a system over repeated use.
The magnetic systems are a mystery to me. I have been told by competitive manufacturers that they work and there are many testimonials in the field from larger vessel owners. Polishing on the other hand is different as it centrifuges the contamination out of the system.
Purifiers were first developed by the navy
and are effective at removing water from the system. There are a few brands out there that I am aware of; Algae-X and Diesel Craft. I am sure that there are others. I am not aware of them.
Conventional fuel additives really do not have an application in marine
environments as they generally do nothing to help with the sludge issue. They contain petroleum distillates that can clean injectors as well as cetane boosters to help with ignition. Cold weather
modifiers are produced by Afton chemical and most fuel additive companies use these ingredients to blend in to their winter blend products.
I will post some results of lab tests in another response.
I have no commercial
relationship with Algae-X.