We have been using a 10 micron primary (Racor 500FG) for the last 22 months (Since we bought Encore), and in the last year, I've had to drain about 1/2" of 'junk' from the filters every few months.
This last week, a trip to Captiva was taken in less than ideal conditions, and we hobby horsed for 3 hours steady. During a routine Engine Room check while underway, I found about 1" of 'junk' at the bottom of one of the Racors (the other was negligible). My manifold allows me to isolate one filter (I use both all the time), which I did, and drained the 'junk'. I filled the filter with fresh diesel, and upon bringing back online, about 1/2 of 'junk' filled the bottom of the clear bowl. During the entire trip home, the engines ran flawlessly at 1700-1800 rpms, but during the 5 hour trip the filter gained almost 1" of (you guessed it) 'junk'. At home, I tested it for water, Negative. I drained the bowl into a clear container and let it settle. Attached is the result.
Alge? Bacteria? Have birds been crapping in my fuel tank?
I replaced the Racor filters with new 10 micron (the old ones had no evidence of green anything in them), but I thought what the heck...Your thoughts?