YSI BOD Analyst Pro - Manual (Page 30)

YSI BOD Analyst Pro ® User Manual 30
Sometimes the seed material is taken from a sample that is already being tested for BOD. As
shown above an influent sample is commonly used since microbes are present in the raw sewage.
Above Influent was assigned in the Seed Control Sample Name field.
In order for Influent
to be in the Seed list
above you will need
to check the box for
“Use as Seed”
during Sample Setup
of the Influent
sample. See the
example to the right.
Sometimes there are
seeded samples for
which both CBOD
and full BOD must
be determined. In
these cases you may
have two seed
control samples of
the same material,
one a CBOD and the
other a full BOD
sample.
Seed control samples cannot be pre-diluted; nor can dilution blanks.
3.3 SEEDING
METHODS
You may choose one of two seeding methods, adding seed material to each bottle that is to be
seeded, or adding seed material to the dilution water.
If you choose to add seed material directly to each BOD bottle, the quantity of seed material is
expressed in milliliters (ml). If you choose this method you must put the same quantity of seed
material in each of the dilutions for the same sample. However, if you have more than one seeded
sample, each sample may have different quantities of seed.
If you choose to add seed material to the dilution water, you must first mix the seed material with
dilution water and use the mix to dilute all of your seeded sample dilutions. Note that the amount
of seed material in each bottle depends on the amount of dilution water in the bottle. The quantity
of seed material is expressed in milliliters per liter, more specifically ml of seed material per
liter of dilution water. Typically the same seeded dilution water is used for all seeded samples.
If you seed directly to the bottle the amount of seed material in each bottle will simply be the seed
quantity (ml). If you seed the dilution water the amount of seed material in each bottle depends on
how much dilution water is in that bottle. Note therefore, that your choice of method will affect
the calculations.