Provided is a water purification material capable of purifying the quality of breeding water without causing any harm to fish and shellfish due to the elution of harmful substances in a fish farm. It consists of porous granules containing calcium silicate hydrate as a main component, the aluminum content is 10% by mass or less in terms of oxide, and the titanium content is 1.0% by mass or less in terms of oxide. Water purification material. The water purification material preferably has a proportion of particles of 0.01 mm or more and less than 0.1 mm in the range of 5 to 30% by mass, a proportion of granules in the particle size of 0.1 mm or more and less than 1.0 mm of 10 to 10%. 50 mass%, the proportion of particles having a particle size of 1.0 mm or more and less than 2.5 mm is 10 to 50 mass%, the proportion of particles having a particle size of 2.5 mm or more and 4.0 mm or less is 5 to 30 mass% %, And a particle size distribution of 0 to 30% by mass of particles having a particle size of less than 0.01 mm or exceeding 4.0 mm.魚介類の養殖場において、有害物質の溶出等によって魚介類に害を与えることなく、飼育水の水質を浄化することができる水質浄化材を提供する。 珪酸カルシウム水和物を主成分として含む多孔質の粒体からなり、アルミニウムの含有率が酸化物換算で１０質量％以下でかつチタンの含有率が酸化物換算で１．０質量％以下である水質浄化材。水質浄化材は、好ましくは、０．０１ｍｍ以上、０．１ｍｍ未満の粒体の割合が、５～３０質量％、粒度が０．１ｍｍ以上、１．０ｍｍ未満の粒体の割合が、１０～５０質量％、粒度が１．０ｍｍ以上、２．５ｍｍ未満の粒体の割合が、１０～５０質量％、粒度が２．５ｍｍ以上、４．０ｍｍ以下の粒体の割合が、５～３０質量％、粒度が０．０１ｍｍ未満または４．０ｍｍを超える粒体の割合が０～３０質量％、の粒度分布を有する。
