BACTERIA IN PURIFIED WATER
Bacteria able to form Colony Forming Units
Epifluorescent (TOTAL) bacteria cell counts
This method yields results in terms of total (living and dead) bacterial cells present in 100ml of sample. Epifluorescent bacteria counts are most often used in conjunction with viable counts. Rising total cell counts are a good indication of slime becoming dislodged, or other issues that put an increased load on the water purification system.
LAL (Limulus Amoebocyte Lysate) or Pyrogen Test for Endotoxin levels
This “endotoxin” assay quantifies the gelatinous, polysaccharide matrix that surrounds gram negative bacteria (most bacteria in the ultrapure water system). Since there is no average amount of polysaccharide associated with a cell, the test results are given as nanograms per milliliter of water.
High port counts
High at pt.of use
Increase flush time until ok
Reduce back pressure
Higher flow rates