Things to know about filters

Here is some information that will help you choose the right filter for your pool.

There are 3 types of filters:

Diatomaceous Earth Filters: The most effective filters are without question the DE filters – some advocates have called them the HEPA filters of pool ownership. Specially treated earth made from extremely fine aquatic fossils (diatoms) will filter out far smaller particles than any of the other varieties, often creating a consistent obstacle for anything above 5 microns. The difference may be measurable not just in the clarity of the water, but in its fungal population as well. The downside is that DE filters require more frequent back-flushing (see FAQ's) than sand or cartridge filter systems.

Sand Filters:  Sand filters are by far the easiest to own and maintain and not coincidentally, the easiest to understand. Filters such as these come in tanks that use simple graded sand to catch anything larger than a given size as it passes through. Depending on the type of sand used, that size is generally in the range of 40 microns well above the threshold for visible dirt and dust. While the 40 micron level is above the filtering levels of the Diatomaceous Earth Filters that filter down to the 8 micron level, the sand filters require significantly less back-flushing to keep them at peak performance.

Cartridge Filters – Cartridge filters tend to be more economical and require less maintenance. This one is easy to understand. Water passes though a filter material and the filter captures the debris. This is just like the water filters used under your sink. Cartridges have much more available area to filter than sand. Most start at 100 sq. ft.  and the majority of the cartridge filters sold are larger than 300 sq. ft. So they don’t clog up as quickly and therefore you touch them less frequently. There are two types of cartridge filters in general. In the first case, there are filters elements that are inexpensive to replace and as such, they don’t tend to last as long. Then there are other filters that have very expensive elements and these last 5 or more years. In both cases, cartridge filters are designed to run at lower pressure than sand. This puts less back-pressure on the pump and hence you get more flow and turnover for an equivalent pump size. Generally these filters have to be cleaned once or twice a season by simply hosing them off, so you don’t touch them as often. In terms of particle size filtered out, cartridge is somewhere between sand and DE.