Purifier full of sludge

This is what happened at a time we board this ship,there is one storage tank which is more than a year without knowing it's legend.
Even previous notes and hand-over never mentioned what the condition of fuel remained inside .
Until such time we tried purifying it with different temperature for purifier.
Every different temperature has a result as what you watch now..
At drydock, found out it was a sticky fuel with a components of sandy particles...