Young Macdonald's Farm Temperature Temperature is a parameter that effects the rate at which metabolize feed, the saturation point of oxygen, and the rate at which the bofilters functions. Rapid changes upset all of the above in the system. The actual system temperature will be determine by the species cultured, but should not vary by more than a few degrees over the coarse of the day. The cultured species will probably not be seriously affected, but keep in mind that a drop of about ten degrees F will reduce the biofilter capacity by 25 to 50%. The biofilter will adjust to new temperatures if you decide to culture a different species in the same system, but it does take time. A good thermometer is all that is needed to check this parameter. NOTE: SEE - Remote water quality management