A fluid composition sensor for detecting fluid particle characteristics, the fluid composition sensor comprising: a housing defining an internal sensor portion and comprising a fluid inlet configured to receive a volume of fluid, wherein the housing is selectively configurable between an open housing configuration and a closed housing configuration; a removable fluid flow component disposed within the internal sensor portion and configured to define at least a portion of a fluid flow path, wherein the removable fluid flow component is configured to be removable from within the internal sensor portion when the fluid composition sensor is in the open housing configuration; a collection media assembly dock element configured to receive a replaceable collection media assembly comprising a collection media configured to receive one or more particles of a plurality of particles within the volume of fluid such that the replaceable collection media assembly is arranged within the internal sensor portion in a particle collection position; an imaging device configured to capture an image of at least a portion of the one or more particles of the plurality of particles received by the collection media; a controller configured to determine, based at least in part on the image, at least one particle characteristic of the plurality of particles of the volume of fluid; wherein at least a portion of the fluid flow path extends in a fluid flow direction that is at least substantially toward the collection media; wherein the collection media assembly dock element is configured to constrain relative movement between the replaceable collection media assembly and the imaging device in a lateral direction. a housing defining an internal sensor portion and comprising a fluid inlet configured to receive a volume of fluid, wherein the housing is selectively configurable between an open housing configuration and a closed housing configuration; a removable fluid flow component disposed within the internal sensor portion and configured to define at least a portion of a fluid flow path, wherein the removable fluid flow component is configured to be removable from within the internal sensor portion when the fluid composition sensor is in the open housing configuration; a collection media assembly dock element configured to receive a replaceable collection media assembly comprising a collection media configured to receive one or more particles of a plurality of particles within the volume of fluid such that the replaceable collection media assembly is arranged within the internal sensor portion in a particle collection position; an imaging device configured to capture an image of at least a portion of the one or more particles of the plurality of particles received by the collection media; a controller configured to determine, based at least in part on the image, at least one particle characteristic of the plurality of particles of the volume of fluid; wherein at least a portion of the fluid flow path extends in a fluid flow direction that is at least substantially toward the collection media; wherein the collection media assembly dock element is configured to constrain relative movement between the replaceable collection media assembly and the imaging device in a lateral direction.