This logo, my first corporate job roughly 13 years ago, was designed after receiving instructions along the lines of "Make us something that looks great."
As the company was, and is, an inovator in water treatment I mixed the imagery of the lightbulb idea with the classic water droplet shape. It was loved.
This is the only logo image I have designed with a gradient which I otherwise avoid completely. I chock it up to my still being new to professional design at the time.