You may be surprised to learn that not all underground pool filters work the same. In fact, there are many different types of systems that you can choose from, depending on the pros and cons of each type. Keep reading to learn more about the various options and how each one stands out from the crowd.
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Shallow-Trench Filters
Also known as ‘pencil’ or ‘pot’ filters, shallow-trench filters are one of the most popular options when it comes to removing dirt, debris, and oils from your pool water. The name comes from the fact that these filters are typically built into the side of a trench that is dug into the ground near your pool. The purpose of the trench is to contain the water in case of a heavy rainfall or an underground dam bursts. Shallow-trench filters work on the principle of gravity. Water flows into the bottom portion of the trench, where it can collect. The dirt and debris at the bottom of the trench settle out as the water slowly flows by. Additionally, as the water flows through the filter media, it picks up the minerals and oils that it comes into contact with. The trapped dirt, debris, and oils are then collected and removed as easily as possible through a regular cleanout process.
Deep-Trench Filters
The opposite of the shallow-trench filter is the deep-trench filter. Just like its shallow counterpart, a deep-trench filter is usually built into the side of a trench that is dug into the ground near your pool. The primary difference is the depth of the trench. Normally, a deep-trench filter is placed at least 2.4 meters below ground, so that even when it rains heavily the water will not damage your pool. The deeper the trench, the better, as the water will settle at the bottom. The dirt and debris at the bottom of the trench will eventually form a thick cake that can be removed through simple excavating or backfilling once a month or so.
No-Trench Filters
Usually, you will find two types of no-trench filters. The first one is the sand filter, which is also known as the ‘French’ or ‘Polish’ filter. The second type is the cartridge filter. Just like their name suggests, these types of filters do not require the use of trenches dug into the ground near your pool. Instead, they are placed above ground on piers or posts, and the water flows through a channel towards the base of the filter, where it is trapped by the gravel-like media. As the water passes through the channel, it picks up the dirt and oils that are contained in the media. Once you have removed the filter for cleaning, all that remains are the piers or posts that held the system above ground. If you decide to go this route, make sure that you prepare the ground before laying the piers, as it will be a difficult task to dig them up once they are in place.
In-Line Filters
Like the name implies, in-line filters are another type of pool filter that you can choose from. These types of filters are connected to the main pool pump in a ‘Y’ or a ‘T’ configuration. When the pump is on, the water flows through the in-line filter and back into the pool. When the pump is turned off, the water stops flowing through the in-line filter and into the pool. Depending on your needs, you can choose an in-line filter with either a Y or T connection. In the Y configuration, the in-line filter is usually placed above ground, with the output channel of the filter leading into a square, open space. The in-line filter in a T configuration is usually placed underground, with the output channel of the filter leading into a U-shaped channel that is connected to the main pool drain.
Backwash Filters
Backwash filters are similar to the other types of pool filters, but their purpose is to prevent the filter from becoming clogged with debris and grit. This type of filter is connected to the main pool pump in a ‘Y’ configuration and is designed to be washed with plain water in order to maintain its cleanliness. A backwash filter consists of a cylinder that is wrapped in cloth and has holes at the bottom for water to escape. When the pump is on, the backwash filter rotates, which serves as an easy way to circulate the water and keep the pool clean. When the pump is turned off, the backwash filter stops rotating and the water gradually settles at the bottom of the container, where it can be removed through a drain or bucket.
Spring-Loaded Filter
Also known as the ‘reed’ filter, spring-loaded filters are usually placed above ground and are designed to be manually squeezed or sprung, when desired. As the water flows between the posts or rails that make up the system, the trapped dirt and oils are then easily removed. While these types of filters are very easy to use, make sure that you clean them regularly and empty the water into your pool once a month or so. Otherwise, you may face serious bacterial infections and other diseases. In most cases, these types of filters are not recommended for use in pools that contain fish, as they may be damaged by the rapid cycling of water flow through the system.
Pelican Filters
Pelican filters are made of a durable plastic and have a unique look due to their unique design. These types of filters are made in Poland and are known for their high efficiency rate and long life span. As the name suggests, the pelican filter looks like a pelican with its beak open wide, ready to catch the water flowing towards its open mouth. Since most pelican filters are made in Poland, make sure to buy one that is of good quality and also purchased from a reputable company, as this may determine the safety and quality of your swim experience.
Dynamic Swimmers
Last but not least, we have the dynamic swimmers. These types of filters are placed on a platform that can be raised and lowered independently of each other. Normally made of transparent plastic, these types of filters are very flexible and are designed to be moved around, depending on your needs. While these types of filters are easy to use and maintain, they normally don’t last as long as the other types, so make sure to clean them more often. In most cases, these types of filters are not recommended for use in pools containing fish, as the water flow may cause the plastic to break down, releasing small, sharp pieces that can become embedded in your flesh.
There you have it. This was a brief description of the different types of underground pool filters that you can choose from. Keep reading for additional information on how to choose the right type of pool filter for your needs.