Abstract: A reservoir accessory assembly comprises a flooring structure being configured to support a fluid processing accessory for the reservoir. The flooring structure comprises a cutout being configured to enable entrance of plumbing from the reservoir for connection to the fluid processing accessory. Side panels are joined to the flooring structure. The side panels comprise screened vents. A back panel is joined to the flooring structure. The back panel comprises a ventilation portion being configured to enable airflow with the vents. A front door is pivotally joined to one side panel to enable access to the fluid processing accessory. A top is configured to cover an interior formed by the flooring structure, the side panels, the back panel and the front door in which the fluid processing accessory is enclosed and accessible via the front door.