how does above ground pool filter work


Author: Poolking - Swimming Pool Equipment Manufacturer

Above Ground Pool Filters: A Comprehensive Guide to How They Work

Maintaining your above ground pool is essential if you want to enjoy a refreshing swim all summer long. One of the most critical components of pool maintenance is the filtration system. Without a functional filter, your pool water can quickly turn cloudy, murky and even become a breeding ground for harmful bacteria. That's why it's essential to understand how above ground pool filters work to keep your pool clean, healthy and safe for you and your loved ones.

In this article, we'll take an in-depth look at above ground pool filters, including how they work and the different types available.

Subheading 1: The Role of a Pool Filter

The primary role of an above ground pool filter is to remove contaminants from the water, including dirt, debris, and microscopic organisms like algae and bacteria. As water is pumped through the filter, the contaminants are trapped by the media inside the filter- typically sand, diatomaceous earth or cartridge filters.

Subheading 2: The Different Types of Pool Filters

There are three different types of above ground pool filters: sand, cartridge and diatomaceous earth (DE) filters. Each has its pros and cons, so it's wise to choose the filter type that best fits your needs and budget.

1. Sand Filters - This is the most popular and cost-effective pool filter option. Sand filters work by pumping water through a bed of fine sand, which traps impurities and particles. Sand filters are easy to install, robust and require little maintenance. Their only downside is that they need backwashing periodically to flush out debris and prevent clogging.

2. Cartridge Filters - These filters use a cartridge made of pleated polyester fiber to trap debris and impurities. Since these filters trap smaller particles than sand filters, they provide a more thorough clean. However, they require more frequent cleaning and replacement than sand filters.

3. Diatomaceous Earth Filters - These filters use a powder made of microscopic diatom skeletons to filter water. DE filters are the most effective option, trapping particles as small as 5 microns. They also require the least maintenance, as DE powder only needs to be added when the filter is initially installed, and only needs to be replaced every 5-7 years. However, they do cost more than sand or cartridge filters.

Subheading 3: How Does a Sand Filter Work?

As mentioned earlier, sand filters work by pumping water through a bed of fine sand. The filter tank is filled with sand, and water is pumped from the pool into the tank. As water flows through the sand bed, the debris and impurities are trapped inside the sand grains. Clean water then flows through the filter and back into the pool. When the sand becomes too dirty and clogged, it's time to backwash the filter. This process involves reversing the flow of water to flush out the dirt, debris, and particles stuck in the sand, so it can trap more dirt.

Subheading 4: How Does a Cartridge Filter Work?

Cartridge filters work by forcing water through pleated filter cartridges. The filters trap debris, ranging from dirt and leaves to bacteria and algae. When the cartridge needs cleaning, it can be easily removed from the filter tank, rinsed and replaced. Once the cartridge is no longer effective, it must be replaced with a new one.

Subheading 5: How Does a Diatomaceous Earth Filter Work?

DE filters work by pumping water through a DE powder-coated grid, which traps impurities and debris as they pass through. The DE powder covers the filter grids and then coated with water. The water then flows through the grids and filter media, trapping debris and particles. The cleaned water then flows back into the pool. When the DE powder becomes too dirty and clogged, the filter must be backwashed, and new DE powder must be added to the filter.


In conclusion, it's essential to choose the right pool filter for your above ground pool, as it plays a vital role in keeping your pool water clean, healthy and safe. Whether you choose a sand, cartridge or DE filter, it's crucial to follow the manufacturer's instructions for maintenance and cleaning to ensure optimal performance. By doing so, you'll keep your pool sparkling clean all summer long.


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