David and Crackerjack are right, I think. In fact, Yellow Out and Green to Clean may be the same thing, just with different packaging. While researching this I came across this FAQ at http://www.yellowout.com/qa/qa.htm:

Q.What is the active ingredient in YELLOW OUT?
A.YELLOW OUT is not an algaecide; it is strictly a pool cleaner. When added to the pool without chlorine, nothing happens. Therefore, it is not required to list ingredients on the container.



Now that's funny.