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. <EOS>