| Key 2 - Filtration | | | | (after initial cleaning & at mid season) to break |
| Now that the water is circulating properly, good | | | | up & remove accumulated greases, oils & |
| filtration removes dirt, debris & even certain | | | | dirt that has become embedded in the cartridge |
| large bacteria & algae. Sand filters remove the | | | | material. Replace the cartridge about every 3 - 5 |
| largest particles, Cartridge filters remove smaller | | | | swimming seasons (one season equals about 4 - 6 |
| particles & DE filters remove the smallest. | | | | months). Please review the note on Chemical Cleaning |
| Let's look at the 3 types of filters & how they | | | | below. |
| work. | | | | DE Filters: DE or Diatomaceous Earth filters offer the |
| Sand filters. All sand filters have 3 things in common | | | | finest filtration available. DE filters use grids or |
| as to their performance: 1. they all use sand (some | | | | "fingers" called septums that hold DE (fossilized |
| older filters may use a combination of sand & | | | | microorganisms) that has the properties of a fine but |
| gravel). 2. Dirty water enters in the top of the filter | | | | gritty powder. DE filters have the ability to filter |
| tank & flows down through the sand which | | | | particles as small as 2 - 5 microns in size (the size of |
| filters out the dirt & debris (down to a size of | | | | algae & even some large bacteria). |
| about 25 - 40 microns - visible dirt & debris). 3. | | | | Water goes into the filter & passes through the |
| Cleaner, filtered water is collected at the bottom of | | | | DE coated septum. Under a microscope, DE looks like |
| the filter tank & pushed out of the filter & | | | | little sponges with tiny holes & nooks & |
| returned to the pool. | | | | crannies that trap all kinds of stuff. The clean water |
| Sand filters are the oldest form of pool filtration or | | | | is then collected & returned back to your pool. |
| water filtration for that matter. Even ancient | | | | In many places you can or are urged to use DE |
| civilizations used sand as a filter to cleanse water | | | | replacements, such as Aqua Pearl, which are lighter in |
| & help make it more potable (drinkable). | | | | weight & more biodegradable than DE. Especially |
| Sand filters have been the most common filters used | | | | compared to sand filters, you don't get just filtered |
| in the swimming pool industry until recently. These | | | | water, you get polished water. |
| filters are great when using non-chlorine sanitizing | | | | DE filters eliminate many pool care problems because |
| products such as biguanides (i.e. BioGuard Soft Swim | | | | of the superior filtration. A DE filter has the capability |
| or Arch Chemicals Baquacil). For most people, sand | | | | to take a dark green, algae encrusted pool & |
| filters will perform a very adequate job. | | | | turn it into a crystal clear paradise in a matter of a |
| Drawbacks: more time needed to filter out fine | | | | few days. Many pool owners notice how less often |
| particles; lots of water (sometimes hundreds of | | | | they "need" to vacuum the pool. However, there is |
| gallons) is "wasted" when backwashing or cleaning | | | | more care needed in maintaining a DE filter. |
| the filter by reversing the flow of water inside the | | | | Drawbacks: DE filters tend to clog up easier - partially |
| tank; sand is heavy. | | | | a function of the fine filtration ability. If you have a |
| Care of Sand filters: Backwash only when needed - a | | | | really dirty pool, the filter may clog up every couple |
| dirty sand filter pulls out a finer particle - usually no | | | | of hours & you may have to change the DE. |
| more than once a week. Chemically clean the filter | | | | That's normal. However, you will reap the clarity |
| about 2 times per season (after initial cleaning & | | | | results in much less time. The other drawback is the |
| at mid season) to break up & remove | | | | waste or used DE. In many municipalities it is |
| accumulated greases, oils & dirt that has | | | | considered a hazard waste material & therefore |
| become embedded in the sand. Change the sand | | | | needs to be treated as such. Check your local |
| about every 3 - 5 swimming seasons (one season | | | | authorities for details. |
| equals about 4 - 6 months) - sand crystals lose their | | | | Care of DE Filters: Clean only when needed. Some DE |
| "sharpness" & are not as well able to trap dirt | | | | filters come with backwash valves while others need |
| & debris. Please review the note on Chemical | | | | to be "bumped". Physically clean (2 times per season) |
| Cleaning below. | | | | the filter by taking the filter apart & hosing off |
| Cartridge Filters: Like sand filters, all cartridge filters | | | | the accumulated dirt & debris from the grids or |
| have 3 things in common: 1. They all use some type | | | | fingers - backwashing or bumping may not fully |
| of pleated fiber cartridge. 2. Dirty water enters in to | | | | remove the used DE. Chemically clean the filter 2 |
| the filter tank & flows through the cartridge | | | | times per season (after initial cleaning & at mid |
| which filters out the dirt & debris (down to a | | | | season) to break up & remove accumulated |
| size of about 10 - 20 microns - much smaller, but still | | | | greases, oils & dirt that has become embedded |
| visible dirt & debris & some algae). 3. | | | | in the septum material. If regularly chemically cleaned, |
| Cleaner, filtered water is collected on the other side | | | | the grids should provide a life of, 7 years or more. |
| of the cartridge & pushed out of the filter | | | | Please review the note on Chemical Cleaning below. |
| & returned to the pool. Some folks notice a | | | | Filter your water for 8 to 12 hours every day from |
| cleaner difference compared to sand filters. | | | | opening to closing. Use a timer so that you don't |
| At one time, cartridge filters were only popular in the | | | | forget and save money. By the way, for the best |
| sunbelt areas. Today, they are used in all parts of the | | | | filtration, be sure to chemically clean your filter about |
| country on all kinds & styles of pools. Cartridge | | | | twice each season to remove accumulations of |
| filters can be used with any pool sanitizing system. | | | | greases, oils & other swimmer and |
| Because of their relatively large filter surface area | | | | environmental waste that clog your pool filter & |
| (the pleated fiber material can be as large as several | | | | that routine backwashing & rinsing will NOT |
| hundred square feet as compared to under 4 square | | | | remove. |
| feet in the largest residential sand filter), cartridge | | | | Why you need to Chemically Clean your filter: As |
| filters generally take a long time to get dirty | | | | noted just above, chemical cleaning of your filter aids |
| between cleanings. A properly sized filter may only | | | | removing greases, oils & other swimmer and |
| need to be cleaned 2 or 3 times per season. When | | | | environmental waste that will soil your filter and |
| sized right, less vacuuming may be needed due to | | | | shorten its life. Normal, regular backwashing & |
| the finer filtration. | | | | rinsing will not remove these wastes. Here's a couple |
| As with all filters, sizing it properly is critical. Never | | | | of analogies that will help you understand the |
| undersize. Never. This is a true case for the axiom, | | | | significance of chemical cleaning: do you use shampoo |
| "you get what you pay for." An undersized cartridge | | | | on when you wash your hair or do you just rinse it? |
| filter MAY initially do the job, according to the sizing | | | | Without shampoo, your hair would be pretty matted |
| charts, but in short time you will be disappointed in | | | | & dirty after a couple of weeks. How about |
| the performance of the filter and in the amount of | | | | dirty clothes? Do you only rinse them out in the |
| work you now need to do. | | | | washing machine or do you add detergent to release |
| Drawbacks: Proper sizing of the filter to do the | | | | & help remove the dirt & greasy stains? |
| proper job. Trying to use an aboveground filter on an | | | | The same thing goes with your pool filter. How do |
| inground pool. Filter must be disassembled & | | | | you chemically clean a filter? That's easy. Use filter |
| cleaned about once each month. | | | | cleaning products such as BioGuard® Strip |
| Care of Cartridge Filters: Clean only when needed. | | | | Kwik® that is used when you can soak your filter |
| Usually about once each month. Cleaning is | | | | (soak the elements or it can be backwashed into a |
| accomplished by taking the filter apart & hosing | | | | sand filter) for a several hours. Spray on products |
| off the accumulated dirt & debris from the | | | | such as BioGuard® Kleen It® work quickly to |
| cartridge. Chemically clean 2 times per season to | | | | remove ground in dirt & oils. |