Abstract: An apparatus for treating a potable water source can the apparatus comprise a solid phase treatment material for treating a potable water source, a solid phase treatment material dispenser comprising a floatation device and a container configured to hold the solid phase treatment material, the container comprising a bottom surface and sidewalls extending from the bottom surface, wherein the bottom surface and/or sidewalls comprise apertures, and wherein the flotation device can comprise a plurality of fasteners attached thereto, and, optionally, a opening securement system comprising a tether in operative communication with the plurality of fasteners and an attachment point about the opening, wherein the tether is configured to permit travel of the floatation device within the water storage tank.