Overview: There are three major types of filtration systems DE, cartridge, and sand filters. Caribbean recommends DE filters because they do a better job catching the microorganisms in the water. Cartridge filters are also a popular option and sand is also available.
Pentair FNS+ DE Filter
DE and sand filters use multiport valves to control the flow of water into, and around the filter. Multiport valves are another added benefit to DE filters because they allow for backwashing. As the grids inside the filter collect material from the water they become dirty and the pressure inside the filter will increase (indicated on the pressure gauge on the top of the filter). This will slow the flow of water and not allow the pool to circulate the water efficiently.
