Abstract: Embodiments disclosed herein relate to novel apparatuses, methods and systems employing said novel apparatuses, and sensors for use with said apparatuses and systems. In some embodiments, apparatuses and systems described herein are used to culture cells and/or detect changes in pH levels or dissolved oxygen and/or carbon dioxide levels in a cell culture sample resulting from the growth of living cells contained within a reaction vessel such as a flask. In some embodiments, said novel apparatuses may be used in combination with a rocker or shaking device or apparatus. The systems and methods may be used to detect changes in pH and dissolved gas levels in a liquid contained in the reaction vessel due to growth of living cells.