This research was funded as an Early Concept Grant for Exploratory Research (EAGER). The work focuses on testing whether earth and ocean tides exert an impact on crustal fluid flow in land and seafloor hydrothermal systems. It uses an unconventional, non-Fourier approach in which forcing functions, derived from the gravitational potentials due to the positioning of the Earth, Sun, and Moon, are used as forcing functions, as opposed to the standard Fourier time series approach that is usually used. Modeling software will be developed that builds off the Admiralty Method time-series approach that uses a pseudo-sinusoidal function whose time-varying amplitude and phase are modulated by the relative positions of the planets. The model will be tested with chemical and temperature data from well characterized hydrothermal systems on land (Iceland and Yellowstone) and on the seafloor (sites on the Endeavour segment of the Juan de Fuca Ridge and on the Mid-Atlantic Ridge). Broader impacts of the work include applicability to the geothermal industry and to the NSF-funded Ridge 2000 program which includes the modeling of fluid exchange between the Earth's mantle and ocean via seafloor hydrothermal vents. Data products and software will be made available in publications and on the Internet.