wave maker

I’v had a debate today about wave makers and how I feel they are unnecessary in fresh water and how it’s over kill perhaps like a sump with a chap who insists my tank needs a wave maker .... I know it doesn’t . He proceeded to tell me that I need one without knowing my tank size or stock ...

So, tank is 105 liters. There is little to no flow in there. So I was thinking, without buying a whole new filter, what options are there? So I was in chat and smelly had just gotten a wave maker. So questions: Would this create the flow I want? Is this a good model...