A package of water treatment pellets includes a first container and a second container. The first container is fabricated from a water-dissolvable sheet material and the first container is filled with and encases the water treatment pellets. The second container is fabricated from a non-water-dissolvable, porous material and is sized and adapted to receive the first container filled with and encasing the water treatment pellets. A water treatment feeder device includes a hollow, box-shaped magazine body defining an internal magazine chamber and a plurality of porous holders disposed in the internal magazine chamber. Each one of the plurality of porous holders retains a respective one of the packages of water treatment pellets. A water treatment feeder system for a structure operative to circulate water thereabout incorporates the water treatment feeder device and the package of water treatment pellets.