Moh. Andri, Budiman and Fabotin Taib (2023) “The Effectiveness of Slow Sand Filtration on Reduction of Iron (Fe) and Calcium (CaCO3) Levels in Water”, International Journal of Health, Economics, and Social Sciences (IJHESS), 5(3), pp. 210-215. doi: 10.56338/ijhess.v5i3.3788.