The main invention for this application is the submersed algae killer for fish and corals keeping aquariums. The vertical valve has a bulbous, cylindrical outer wall having an upper flange connecting to a wet-type hydrant by a break ring and a lower flange connecting to a system riser pipe. The noise value N has a value equal to a product of a random number, the value \u201crate\u201d, and the value \u201ccoefficient\u201d. At the scheduled activation time, each web server copies data from its staging cache to an active cache in the web server.