Foamy scum.

[Oilybloke]

A delivery today has got me a bit worried......he's running a 50/50 blend and his bulk storage tank has a scummy, foamy film floating on top of the mix. A sample shows the fuel underneath is perfectly clear, but it doesn't look too good. Any suggestions what this might be? (Apart from foamy scum, of course!)

[Head Womble]

Is this bio that you have produced or from another supplier ?

[Bill]

Ohh its a technical query.
I thought foamy scum was a new way of insulting someone!

[Oilybloke]

Is this bio that you have produced or from another supplier ?

It's my produce. I use KOH, never accept anything other than a perfect 10/90 test, mist wash until water is clear, bubble dry, then eco. I'm wondering if it's temperature related, although it's not particularly cold over here; we have had no frosts and it's presently 10c. I can't see any problems with other stock in my shed. Could it be 'diesel bug'?

[Head Womble]

Is this bio that you have produced or from another supplier ?

It's my produce. I use KOH, never accept anything other than a perfect 10/90 test, mist wash until water is clear, bubble dry, then eco. I'm wondering if it's temperature related, although it's not particularly cold over here; we have had no frosts and it's presently 10c. I can't see any problems with other stock in my shed. Could it be 'diesel bug'?

Froth/foam on top can sometimes be excess soap, but with your washing process this should not be the case.

[Jamesrl]

Could it be 'diesel bug'?

Highly unlikely,  diesel bug will block a fuel filter in very short time and replacing an element makes no difference unless the whole fuel system is completely cleaned at the same time, and I mean the WHOLE system.