A 6-place BOD testing system for measurements of up to 4000 mg/l. Provides precise measurements of BOD, based on the manometric principle, where no water dilution is needed. Each of the 6 positions can be started, run and measured independently. The measurement period can be selected by the user between 1 and 28 days to suit the application. The system is easy to use with no awkward tubing and can be set up in approximately 10 minutes.