A device (1) for dissolving a gas (G) in water (W) is provided, and includes a housing (100) configured to be submerged into the water (W) with the housing (100) having at least one water inlet (101), a gas inlet (102) and at least one water outlet (103) for discharging gas enriched water out of the housing (100), a pump (5) in fluid communication with the at least one water inlet (10) for sucking water (W) from a surrounding of the housing (100), the pump configured to generate a main water stream (S′), and means for injecting the gas (G) supplied via the gas inlet (102) into the main water stream (S′). The device (1) includes a probe (6) configured to measure a concentration of the gas dissolved in water, and the probe (6) is arranged in the housing (100) of the device (1).