I know its a bad title,but last week my mate broke down,he thoughthe ran out of diesel but gauge was saying thrd of a tank,our fitter came out and after 3hrs got him going.Back in garage tanks drained the was lots of littlt black modules, had them tested found out it was a yeast defecked,which is thrush,has anyone else had this problem
alf apsey:
thrush,has anyone else had this problem
Not personally Alf. 
But if your mate has that problem again this link might help 
It comes recommended my a friend of mine. Dr.Google. 
Boats get this a lot although it is usually down to bacteria eating the hydrocarbons in the fuel especially in tanks that have been left not full for a long time.
I worked for 17 years, aircraft refuelling and this was known as micro biologicall growth. It occurs when there is water present in the tank and the growth develops in the interface between the water and the fuel. Obviously, we didn’t want this to get into aircraft tanks because if they get a fuel blockage the engines would stop and they would be stuck in the sky forever. 
There must have been some contaminated diesel put in there sometime.
Our place has just had the same problem,it was blocking up the filters on our 06/56 Daf 85 but not on our 59 plate volvo’s or 07 plate M A Ns or the 10 plate Actros’s 
the fuel supplier came out and drained our tank and all seems well now,fingers crossed
I posted some where else about water separators these are still in use by
many firms who know about the ill effect of bad fuel,this is a
EXAMPLE
here is another EXAMPLE
They just need to drain the water out of their storage tanks from time to time. You will find it at the bottom!
bowserman:
Obviously, we didn’t want this to get into aircraft tanks because if they get a fuel blockage the engines would stop and they would be stuck in the sky forever.
diesel bug is the usual slang name, get it lots on boards and can be a right PITA! There are people that will come out, drain your fuel, filter and treat it then put it back in.
My 56 plate Man TGA’s have this affliction.
This sort of thing is becoming more of an issue over here in the USA, it’s only started happening since the introduction of ultra low sulphur dieseasal, it’s more of an algae than a yeast though, all black & slimy, another cause is hot return fuel breaking down into tar, the Yanks call it Asphaltine 
It’s worse on EGR engines as they run a lot hotter. If you continue to suffer from it (algae) the best way to deal with it is to go to a Marina & buy an Algae remover, it’s common in boat engines & they have a number of products that will get rid of it, none of them are cheap though & you’ll be swapping filters every couple of hours until it’s cleaned out the whole system
bowserman:
‘…aircraft refuelling … micro biologicall growth …’
Yes, or if life is full of emptiness at the moment, Google cladosporium resinae to learn some horrible truths about fuel contaminating beasties and their horrible side effects.
We found after the addition of Bio diesel to the fuel the last couple of years that the grow of Bacteria was very high, causing al kinds of trouble. 
Bacteria need 3 things to grow, warmth, water and feed, warmth will come from you diesel return line and can heat the diesel tank up to 30 degrees under certain circumstances, this causes condensation in the tank when he cools down overnight, and the bio? Diesel is the Take away delivery service for the bacteria.
When we had high sulphur diesel, the problem was reduced due to the sulphur not being very nice to the bacteria.
In a warm climate this can cause a tank in one night to get a lot of black slimy threads floating in your tank, causing your filters to block.
On the continent BP has a diesel called TRAXX that should clean this up and reduce the grow; I don’t know if there is something similar in the UK. 
So again every advantage has a disadvantage (bio fuel reduces the use of fossil fuels, but brings new or accumulate old problems):mrgreen: