Clean Master says that it helps you boost your phone’s memory and clean junk files to maximize storage but it actually slows down your phone. Please stop using it as you may be killing the performance of your phone. The only case you could use an app like clean master is when you’re low on storage and need to clean the cache from all apps. It is totally unnecessary app and you should not install it on your phone.
Use the default task manager instead. This app also consumes more battery and data in background.