Which is finer, 20 or 50 micron?

Common Micron Sizes Explained

50 micron filters: Catch sand, dirt, and large particles. 20 micron filters: Trap finer grit and visible sediment. 5 micron filters: A popular choice for homes, protecting appliances and improving clarity. 1 micron filters: Capture very fine sediment and even some cysts or microorganisms.