Microorganism infestations in fuel and lubricant tanks (including bacteria, yeasts, molds, and algae) can occur with every filling of the tank, due to ventilation and contamination. Microorganisms can survive, grow, and reproduce only in the water phase of a medium. This unavoidably occurs during transport and storage, primarily due to condensation.The potentially severe consequences of an infestation: loss of quality of the diesel or lubricating oil. The microorganisms and their metabolic products clog filter elements, diesel, and oil lines, as well as water separators and injection pumps. Even tank walls and pipe work can be destroyed."Water concentration" is thus the deciding factor that must be reduced. This is possible using a permanent fuel and lubricant treatment that prevents the water concentration from exceeding 60 ppm.