What you will find is few different approach for a cleanup crew.everyone is right.
I will tell you from my experience.
I have tried all types of snails and crabs and yes they do a great cleanup,but as your tank starts to mature you will lose few of them and eventually will require to keep on buying more.
For my setup and I think you seen it.
A good Rodi water continuously scheduled water changes,good skimming,and ample amount of HCGFO with carbon does the trick in my system without a spec of algae,ton of water movement and my sump is full of live rock.hope that helps.