A water treatment system is provided. The system includes a container holding a reactant liquid within the container. The system further includes an electrode capsule removably retained within the container and submerged in the reactant liquid. The electrode capsule operates to generate reactant gas by operating within the reactant liquid. The system includes a cap releasably coupled to an opening of the container. The cap includes a nozzle that allows flow of reactant gas out of the container to treat an amount of water.