Hydration systems with improved fluid reservoirs. The reservoirs include a fill port with a neck having an opening. The hydration systems further include a closure member, such as a cap, that selectively seals the opening, and an elongate drink tube through which a user may draw drink fluid from the reservoir. The hydration systems further include a wrench assembly that extends around the neck and includes handle that projects generally away from the neck. In some embodiments, the wrench assembly provides a counter lever to assist in the removal or coupling of the cap onto the neck. In some embodiments, the wrench assembly is removably mounted on the fill port, and in some embodiments, the wrench assembly is fixed secured to the fill port. In some embodiments, the wrench assembly is rotatably coupled to the fill port and in other the wrench assembly is non-rotatably coupled to the fill port.