Diamond Diesel Fuel Polishing

Diesel Fuel Sampling and Onboard Testing - Marine

Sampling should be done annually. Samples should be drawn from the bottom of each tank as this is where sludge, water and particulate matter will settle.  This sample will provide a visual inspection of the fuel and will indicate any obvious problems.

If contamination is evident, on board testing can pinpoint the problem.

Onsite Diesel Tests:

  • Clarity:  evidence of sludge, mold, bacteria and other contaminants
  • Water:  free standing water accumulates on the bottom until stirred up
  • Moisture:  fuel appears hazy
  • Mold:  active growth
  • Bacteria:  active growth


If significant free standing water is evident an additional test can be done to identify the depth/volume at the bottom of the tank.

Actual mold and/or bacteria growth must be addressed immediately. A quality biocide should be used to kill the microbial growth. Frequently the growth is so pervasive that strands of the bacteria can be seen growing in the glass bowl of your fuel/water separator as well as mold attaching itself to the sides and top of your tanks.

A visual inspection of the inside of the tank using a color micro inspection camera can be done if a heavy indication of mold or bacteria is detected.