Water is the preference of choice as an algal medium in a recent EPA manual (Stevenson and Bahls 1999) and with researchers for studying non-diatom algae. Other studies use syrup mediums (Patrick 1936, Stevenson 1984, Taft 1978) and Pleurex (Hanna 1949, Von Stosch 1974) to study primarily phytoplankton. Syrup medium uses a gluteraldehyde solution, a known carcinogenic substance, to fix the algal cells before mounting. Pleurex is not commercially produced. It is a labor-intensive procedure to make in the laboratory and is not a favorable medium for all algal species (Von Stosch 1974). Typical sealers for water-based slides are fingernail polish and polyurethane (Stevenson and Bahls 1999). These sealers are permeable to water vapor, and the sample gradually dries out within days to weeks for fingernail polish and a few months for polyurethane. While I have used both fingernail polish and polyurethane, I prefer epoxy as a major improvement to other sealers.