A more experienced colleague mentions to you that you should aim for a dissolved oxygen concentration around 1.0 mg/L at day 5 of the experiment. They show you data from a similar wastewater spill that happened last year, in which the BOD5 of the stream water was 60 mg/L. From your previous experiment, you found that the dissolved oxygen concentration at day 0 was 10 mg/L. Based on this information, what dilution factor, P, should you try in your reactor?