Sand filters are one of the most popular ways to filter water, and for good reason. They are simple, effective, and require very little attention. The pool water flows through the sand and travels down to the bottom of the filter, collecting and trapping dirt and debris, down to 20-40 microns. The clean water exits the bottom of the sand filter and re-enters the pool. Sand filters must be backwashed every few weeks to clean out the dirt and debris that was collected.
Cartridge filters are the simplest filters available. The cartridges offer a large filtration surface area, allowing them to filter down to 10-15 microns, and have fewer clogs than sand filters. Cartridge filters run at lower pressure than sand filters, resulting in demands on your pool pump, less wear and tear, more flow, and greater water turn-over. Cartridge filters should be cleaned once or twice a pool season by simply removing the filter and hosing it off. You can make this step easier, and more effective, by using a filter cartridge cleaner, as well.
Diatomaceous Earth offers the highest level of filtration available for your pool. D.E. is able to filter down to 2-5 microns which is far smaller than is visible to the human eye. D.E. is produced from fossilized exoskeletons of tiny diatoms. This material is used to coat the grids in the filter house, and act like tiny sieves to filter out extremely small particles of dust and dirt. This produces unsurpassed water clarity.