On the Pool School here and various other sites the DE filter is always listed as 3-5 micron, cartridge filters are usually between 5-15 and then sand coming in even higher particle size. Since these numbers seem fairly consistent no matter where you look, just where did these results come from? Any links to independent tests available?
Being a new pool owner I was taking these numbers as "gospel"
.". What led me to question this was another online vendor with almost the same pool school having their description of Peantair's cartridge filters having the ability to filter to 30 microns. Pentairs own website lists their super duty cartridge in a cartridge having a 20 micron ability.
So, just where did all the filter numbers come from?