diesel fuel turning black

[kittie]

Our diesel (red) fuel is turning black, have set up filters as a mini polishing system, and have cleaned the racor filter head, replaced the filters. Any suggestions ... could this be algae?

[HerbDB]

Absolutely. Get a diesel treatment to stop the growth, but if the tank is already gunked up, you will still need to clean the tank and polish the fuel.

[Capnblu]

RICH H cleanup on aisle 2!
Do what Rich says, or look up his posts what he's told others!

[dieselboy]

It would help if you stated what type of Diesel engine. Some engines can transfer high pressure engine oil to the fuel system in some type of injectors.

[pdqaltair]

Originally Posted by kittie

Our diesel (red) fuel is turning black, have set up filters as a mini polishing system, and have cleaned the racor filter head, replaced the filters. Any suggestions ... could this be algae?

...by running a culture. It's easy.

Sail Delmarva: Diesel and Biocides

Once you have an answer, chose a biocide. You may also need to clean the tank. The polishing filters will try, but cleaning is far better, to make a fresh start.