The Total Coliform / E. coli Indicator Bacteria Test Kit (Code 4-3616-UV) includes five tubes, each with a nutrient tablet. The five tubes are inoculated with 10 mL of sample water each and incubated for 24 to 48 hours depending on the ambient temperature. A change in the color due to acid production and the formation of gas bubbles in the reconstituted gel indicates the presence of coliforms.