YSI BODAnalyst - Manual (Page 61)

Customizing Your Program Section 11
YSI Incorporated BOD Analyst for Windows Software 57
The maximum acceptable value of BOD for tests with the sample name Standard. The default
value is 237 mg/l (or, 200 plus 37).
Check Coefficient of Variation
Calculates a Coefficient of Variation (CV) for all dilutions in a sample and checks that value
against the CV limit. If the CV limit is exceeded, the lowest concentration dilution is removed
from the average and the CV is calculated for the remaining dilutions and the CV is checked
again. This process is repeated until the calculated CV is within limit or only one bottle remains.
Coefficient of Variation Limit
The maximum acceptable CV for sample BOD data. This number is typically the CV of GGA
standard tests performed by your laboratory. Default is 0.35.
Apply Criteria after Final Readings
If checked, each bottle is automatically checked against the criteria when the Final DO readings
are complete. Alternatively, the CHECK Button on the Bench sheet form can be used to check
all bottles at any time.
11.4 THE GENERAL SETTINGS FORM
You can bring up the General Settings Form by selecting Setup / General from the Main Menu.
The form is used to set the normalization factors and other options.
Normalization Factors - The program will multiply all depletions by the normalization factor for
the day of the final DO. For the typical 5 day BOD, enter the pair (5, 1.00). If you perform 20
day or 7 day BODs, enter either (20, 1.00) or (7, 1.00). Up to 20 pairs can be entered, with days
ranging 1 to 99, and factors ranging 0.00 to 2.00. If you want to estimate a 5 day BOD from
finals done on the 4th or 6th day, enter pairs like (4, 1.13) or (6, 0.91).
Derive initials: You do not need to measure initial DOs for every dilution. The program can
derive the initial DO of a dilution based on the initial DO of another dilution of the same sample,
the initial DO of the blank, and the initial DO of any seed or spike that may be present. If you
want to use this feature, check the Derive initials option. Just skip over the dilutions that you