Solar tracking water purifier

I wanted to learn more about alternative energies, and came up with a project to use solar cells to run an autonomous, scalable water purifier.  The high level block diagram consists of a few major pieces:  1)solar tracker/charger and battery, 2)water pump, filtration, and barrel/storage, and 3)on demand purification.   The overall idea is to have a deep cycle marine battery that is charged efficiently from solar cells to provide all the power to the system.  When the water in the barrel gets low, a low voltage, slow pump would start to fill the barrel.  And when a user puts a container under the spigot and pushes the button, filtered water would flow through an ultraviolet lamp/tube at a rate that kills all bacteria and viruses.   An Arduino microprocessor would monitor inputs and outputs to coordinate the actions of the three main pieces, based on user inputs.  So far, we have built a prototype of the solar tracker that tracks the path of the sun and aims the solar cells directly at the sun for maximum efficiency.  We are using a simple set of solar cells, with a diode in line to prevent reverse current from the battery, when the solar cells are in the dark.