Cartridge Filtration.  This methodology employs an element or elements similar to the air filter in your car. Debris in the water passes through the filter and is trapped by tiny pores in the cartridge(s) within the filter. When the filter elements become dirty, you simply remove the elements from the filter and hose them off. Of course, you can also use some filter cleaning agents to get the cartridges even cleaner. Typically, cartridge filters trap particles as small as 10 – 15 microns in size. The human eye can’t see anything smaller 40 microns.