Sprayer devices and related methods. The sprayer devices can be of a type that may be carried or worn on the back of a user. Each sprayer device has a tank, a spray outlet (e.g., a spray nozzle or spray wand) and either a manual or power pump. The sprayers may also incorporate one or more of the following: a) a brace member for deterring bending or deformation of a bottom bracket on the sprayer, b) a pump axle with redundant rotation-limiting stop members useable for either right-handed or left-handed operation, c) system for selective and/or controlled agitation or non-agitation of liquid within the sprayer tank and/or d) an information card holding niche with removable information card.
