To be honest there are many different formulas to pick from. I got a bottle of this at the store when I purchased my new Big Green Machine and was very pleased with the results. I have light colored carpet and find it does the job for me. It does a great job on the main areas of a room, the high traffic sections and my steps. My carpet was installed many years ago and my first thought was to just replace it. After using this formula there is no need to replace the carpet saving me thousands of $$$$.