Buildup in fuel tank..

[coyotegray]

I'm not sure if this is biological or mineral or some other type of contaminate but I discovered it in my 003 today while changing the fuel cap gasket. The cap has been lose for a while and I run off an aux tank so I don't open it very often..


Any ideas.. If feels like sand but turns to a paste if you rub it..

 

[AceHigh]

Algae

 

[pctrans]

Not algae. Corrosion. Cleans up pretty good with white vinegar.