sta rite system 3 cardtidge as good as de?

[waterbear]

You might want to consider moving it to the china shop then. Channeling can occur even in a free flow sand filter that is not pressurized. It is the nature of the beast when filtering with sand. Organics, oils, and scale can collect on the sand and backwashing will not effectively remove them and over time they will take their toll. These same organics, oils, and scale also cause DE to clump and bridge and are what effectively 'wears out' a cartridge. It is true that a pump that is oversized can cause channeling and other problems but that is not the only reason it occurs. Cleaning the sand and declumping it is not the same as replacing the sand. All filter mediums get dirty with use and a dirty filter medium reaches a point where it is just not as effeicint anymore.