PROBLEM TO BE SOLVED: To provide a water modification apparatus for suppressing breeding of moss in a water tank for breeding fish and shellfish.SOLUTION: A water modification apparatus is installed on an upper part of a water tank, and water in the water tank is pumped up to an upper part of the water modification apparatus and discharged from a discharge pipe. The discharged water gravitationally drops while tracing the surface of moss, and flows down again into the water tank from a lower part of the water modification apparatus, to thereby circulate between the water tank and the water modification apparatus. In the process of the circulation, a nutrition contained in the water is ingested by the moss outside the water tank, and the nutrition necessary for growth of the moss is removed, to thereby modify the water quality in the water tank into an environment unsuitable for breeding of the moss.SELECTED DRAWING: Figure 1【課題】魚介類の飼育用水槽における苔の繁殖を抑えるための水改質装置を提供する。【解決手段】水槽の上部に水改質装置を設置し、水槽の水を水改質装置の上部まで揚水して放水管から吐出させる。吐出された水は苔の表面を辿りながら自然流下し、水改質装置の下端部より再び水槽内に流れ落ちることで、水槽と水改質装置の間を循環する。この循環の過程で水に含まれる栄養素が水槽外の苔に摂取され、苔の生育に必要な栄養素が除去されるため、水槽内の水質を苔の繁殖に適さない環境に改質することができる。【選択図】図１
