Hi, I think you need to visit the Android Lounge. Here is a link to guide you:
Android Task Killers Explained: What They Do and Why You Shouldn't Use Them
I downloaded info several months ago written by a Techo who writes Software and Programs for Android use. He stated quite firmly that "Task Killers" should NOT be used on Android phones as the system OS is Linux and is 'cached' and doesn't use battery power until requested.
Read the article in the link above and see if it helps. Cheers Neil.