Lighting for my tank

[AndyH]

I've got a 3 gallon Supershrimp tank that gets little to no natural sunlight. The tank has to stay where it is, so moving the tank to a sunnier spot is not an option...
Currently, there is a tall Walmart lamp right beside the tank. The lamp has one of those moveable arms that I've positioned to shine right above the tank. It holds standard light bulbs. The bulb I have now is a 26w 120v standard Fluorescent bulb with a 6500k white color that I got from Home Depot around 3 years ago. I read somewhere that the light output of Fluorescent bulbs decreases over the years even if you don't notice it. Obviously the bulb is still bright enough for lighting the room, but I was thinking about replacing it, especially since the main purpose of the bulb is to light the Supershrimp tank now.
So what does everyone else use for lighting small Supershrimp tanks? Ideally it would fit in the same lamp socket and give off a similar white color. Should I just go get another standard Fluorescent bulb from Home Depot? Is there a similar bulb that is specifically designed for aquariums that I could get from a Petco or something? That still fits in the same socket? Or is there something entirely different?
Thanks for any help and ideas.

[KenCotigirl]

Andy I am frugal. Since you do not have a planted tank light quality is not as important. The shrimp certainly do not need the light. As per Mustafa the macro algae is not very particular about light. So replace the bulbs as you see fit or when they burn out. I use the 6500k bulbs.

[Mustafa]

I concur with Cotigirl...don't worry about your light. Sounds like your light is more than enough. And fluorescent lights don't just indefinitely lose output. Their light output decreases quite a bit within the first half a years, but then stays relatively stable until the bulb dies. I am using shoplights with several year old bulbs in them.