There have been a number of articles regarding ram management. Empty ram is useless ram. The phone clears ram as it needs it automatically. i can never understand why people think they are smarter than the built in logic of ram management the engineers have programmed into the phone. Ram will only stay empty till the next thing you do with your phone. Then it fills right back up as it was designed to do.
Why believe a app developer trying to promote their app over the people that designed the phone. Apple has removed a number of ram management apps. People have been screaming for more ram, now they have it and they want to manage it manually? Apple's ram management is one of best in the industry. That's why they got away with less ram than others for years.
There are some apps like Facebook that do run in background regardless of how you set them. You would benefit by closing those apps down when not in actual use. This closes the app as well as flushing any ram dedicated to it that might still be in ram memory.