To provide a low-cost reservoir system for maintaining the freshness of the fish by increasing the amount of dissolved nitrogen to lower the dissolved oxygen amount of the liquid in the reservoir in the tank . The apparatus includes a storage tank 6 , the storage tank system 1A equipped with a cooler 2 , storage tank in order to lower the amount of dissolved oxygen in the liquid passing through it to increase the dissolved nitrogen content is converted into nitrogen dissolved solution nitrogen gas injection device 3 which is located outside of , the liquid circulation means including a liquid circulation pump 4 for circulating it back into the reservoir tank after passing through the nitrogen gas injection device is taken out of the liquid from the reservoir , and comprising a nitrogen gas injection device comprises a nitrogen gas extractor 32 for extracting the nitrogen gas from the atmosphere , a nitrogen gas injector 33 for injecting the liquid to pass through the extracted nitrogen gas . [ Selection Figure ] Figure 1【課題】貯液槽内の液体の溶存酸素量を低下させ溶存窒素量を高めて魚の鮮度を維持するための低コストな貯液槽システムを提供する。【解決手段】貯液槽6と、冷却機2とを備えた貯液槽システム1Aにおいて、通過する液体の溶存酸素量を低下させ溶存窒素量を高めて窒素溶存液に変換するべく貯液槽の外部に設置された窒素ガス注入装置3と、貯液槽から液体を取り出し窒素ガス注入装置に通した後に貯液槽内に戻すように循環させる液体循環ポンプ4を含む液体循環手段と、を備え、窒素ガス注入装置は、大気中から窒素ガスを抽出する窒素ガス抽出器32と、抽出した窒素ガスを通過する液体に注入する窒素ガス注入器33とを具備する。【選択図】図1
