Pool and Spa 411

The Critical Importance of Proper Filtration

Filtration filters out the micro-organisms, dirt and bacteria feeding particles that cause algae and other forms of bacterial growth, resulting in clearer and healthier water.

The most common 3 filters that are used in swimming Pools are: Sand (Silica) Filter, Diatomaceous Earth and Cartridge Filters.

The oldest and most commonly used method of filtration, a Sand Filter is a tank-shaped filter that utilizes a special grade of sand, as a filter media.

While not considered the most effective of filter systems available, it is definitely a Fan favorite - results can be improved through regular maintenance and the periodic use of water clarifying products such as Filter Perfect by Natural Chemistry.

A common mistake with Sand Filters is backwashing too often. The reading on the sand filter’s gauge is an indicator the effectiveness of filtration and helps to identify when backwashing is required. Consult your manufacturer’s instructions to optimize this system, or stop by English and Lepage to discuss what will work best for your system setup.

Also, incorrect operation of the position valve can lead to mechanical failure of the valve around the seal. In addition this can lead to the valve breaking or render it unable to securely hold the position required for the operation in process.

*  While by no means considered necessary, the efficiency of a sand filter may be significantly improved by adding a layer of Diatomaceous Earth in your sand filter tank. Diatomaceous Earth is a porous powder with microscopic openings, that, when magnified, look like tiny sponges. Clear water can pass through these openings, but particles as small as one to three microns, are trapped during the first pass through the media. *

How a Sand Filter Works

With a Sand filter, water is filtered from top to bottom. Inside, a  special filter sand (called silica sand), which has sharp edges that separate and trap particles, causes filtration to take place.

Water is moved in two directions through this filter system. On the filtration cycle the water comes in through the top and filters down through the sand into the multi-lateral under-drain assembly. On the backwash cycle the water runs down and out this assembly forcing the contaminates and debris out of the sand enabling them to be flushed out of the system.

The 6 Valve Settings of a typical Sand Filter:

1. Filter / Filtration
2. Backwash  
3. Drain / Waste
4. Whirlpool / Circulation
5. Rinse   
6. Winterizing/Close

Tips for Sand Filter Usage

1. Always turn off the pump before changing positions on the valve to release pressure.
2. After replacing sand ensure that the valve is reaffixed in the appropriate position.
3. Always do a complete full turn to protect the seal.
4. When using the drain or waste position, always fill the pool as high as possible first.
5. The Whirlpool, Recirculate or Circulation setting is best for mixing chemicals into the water quickly without filtering. –IE: when using floculents such as Power Floc by Bio Guard.
6. Backwash when your filter gauge has increased from its normal running pressure by 8 to 10 psi.
7. Backwash until the water in the spyglass is clear or until water at end of drain is clear. It is recommended to follow the manufacturers directions using the filter gauge. Each backwash should be followed with a rinse for 20-30 seconds.
8. A Sand Filter should be cleaned upon opening or closing your Pool for best filtration results.

The Cartridge Filter

A Cartridge filter is a type of filter that utilizes a porous, pleated component or bag to remove particles. Cartridge Filters are very commonly used in spas as well. This type of filter should be chemically cleaned on a regular basis allowed to dry completely before installation to maintain performance.

How to Clean a Cartridge Filter:

1. Use appropriately diluted filter cleaner in a bucket of warm water.
2. Put cartridge in bucket; keep it upright until it is covered with solution and let it sit this way for 5 to 6 hours.
3. Immediately rinse the cartridge with cold water or let it soak in a bucket of clean water.
4. After rinsing dry thouroughly

SEE ALSO FAQs Pool Sand Filter