Effectiveness of the Combination of Alum (Al₂(SO₄)₃) and Calcium Hydroxide (Ca(OH)₂) Coagulants in the Removal of Manganese (Mn) Using the Coagulation-Flocculation Process: Efektivitas Kombinasi Koagulan Alum (Al2(SO4)3) dan Kalsium Hidroksida (Ca(OH)2) pada Penghilangan Logam Mangan (Mn) Menggunakan Proses Koagulasi-Flokulasi. Stannum. 2024;6(2):71-78. doi:10.33019/jstk.v6i2.4301