A chemostat refers to a bioreactor to which fresh medium is spontaneously supplemented, and the culture liquid comprises the leftover nutrients, the metabolic end components, and microorganisms are spontaneously withdrawn at the similar rate to maintain the volume of the culture constant.
In the given case, possibly the lack of growth is mainly taking place due to the dilution of culture too briskly for the bacteria to differentiate and remain in the culture vessel. Thus, the problem can be corrected by bringing down the rate of dilution.