LaMotte EZ 3-0034 - Manual (Page 3)

bulb to draw the water into the dropper. Carefully squeeze the bulb to expel
excess water until the dropper is filled to the desired sample volume.
Use these gen eral guide lines for de ter min ing sam ple vol ume to be tested:
• If the coliform level is unknown, begin with 1 mL. This sample size is
recommended for sources such as rivers, ponds, streams, lakes, ditches, etc.
These samples often have moderate amounts of coliforms. If counts are too
low, increase the sample size.
• If counts are too high for water samples with extremely high coliform levels, the
sample size can be reduced to 0.25, 0.5 or 0.75 mL.
• If the sample is suspected of having very low levels of coliform, such as
drinking water, use a 5.0 mL sample size.
4. Remove the cap from one bottle of Coliscan Easygel. Do not touch the neck of
the bottle. Do not touch the inside of the cap or put the cap down where it could
become contaminated.
5. Add the water sample from the dropper to the bottle of Coliscan Easygel. Hold
the bottle and dropper at an angle to prevent spills. Carefully squirt the sample
into the bottle.
6. Cap the bottle and swirl to distribute the contents. Do not shake or create air
bubbles.
Note: After the addition of the water sample to the Coliscan Easygel bottle,
samples that can not be plated within 10 minutes should be kept on ice or
refrigerated. Keep the bottles out of direct sunlight.
7. Remove the tape from one side of the dish and lift up the lid. Pour the mixture into
the Petri dish bottom.
8. Replace the lid on the Petri dish. Carefully swirl the poured dish until the bottom
of the dish is completely covered with liquid. Do not splash the liquid over the
side of the dish or onto the lid. Tape the dish shut.
9. While the contents of the dish are still liquid, place the dish with the lid side up in
a warm level spot or in an incubator. The liquid will solidify in about 30 - 45
minutes.
10. When the medium has solidified. Turn the dish upside down (with the lid side
down). Incubate Petri dish for 48-72 hours at room temperature (68-74°F or 20 –
24°C) or 24-48 hours in a preheated incubator at 95°F (35-37°C). See
Incubation Hints.
Note: A liquid may form during incubation. Avoid spilling the liquid. If liquid
spills, observe safety procedures; disinfect the spill area and wash hands
thoroughly.
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