Tank bromeliads are a subset of plants that live epiphytically (on top of "host" trees) and are common to the canopy of tropical forest environments. Such bromeliads lack true roots, instead growing leaves in a "tank" like structure in which water pools and by which water is absorbed. The water in these tanks often has a remarkably low pH. The mechanisms of how such low pH is reached are not clear, and may involve many variables, including the tree host, the bromeliad, and the microbial community within the tank. In this study, we investigated the effect of host tree leaf litter on the pH of bromeliad tank water. Werauhia gladioliflora tank bromeliads were kept in a shade house at La Selva Biological Research Station, Costa Rica. Leaves from three trees that commonly host W. gladioliflora were gathered and deposited into the bromeliad tanks as well as artificial tanks. The pHs of these tanks were monitored throughout June and July 2010. Additionally, microbial communities in the tank waters were surveyed and growth of the bromeliad leaves was monitored. The data suggest that the species of leaf litter present does have a marked, consistent influence on the pH of W. gladioliflora tank water. Of the host species tested, two were correlated with pH increase and one with pH decrease as compared to tanks without leaf litter. This project contributes to a growing understanding of the complex and dynamic relationships involving and contained within tank bromeliads.