Real-time monitoring for environmental factors(temperature, salinity, chlorophyll, etc.) and carbonate components( pH and ) was conducted during 5-6th of July, 2012 at a seaweeds farm in Gijang, Busan. Surface temperature and salinity were ranged from and 33.7~34.0, respectively, with highly daily and inter-daily variations due to tide, light frequency(day and night) and currents. Surface and pH showed a range of and 8.03~8.15, and chlorophyll-a concentration in surface seawater ranged 0.8~5.8 . Environmental and carbonate factors showed the highest/lowest values around 5 pm of 5th July when the lowest tidal height and strongest thermocline in the water column, suggesting that biological production resulted in decrease of and increase of pH in the seaweed farm. Processes affecting the surface distribution were evaluated using a simple budget model. In day time, biological productions by phytoplankton and macro algae are the main factors for drawdown and counteracted the amount of increase by temperature and air-sea exchange. The model values were a little higher than observed values in night time due to the over-estimation of physical mixing. The model suggested that algal production accounted about 14-40% of total variation in seaweed farm.