When selecting equipment for your pool, chances are you are a little overwhelmed at all the options available to you. Not only are there tons of choices, but there are also multiple different types of filters as well. In this guide, we will briefly discuss the different types of pool filters, their relative merits, and downsides, and discuss how to go about choosing the filter that will work best for your needs, preferences, and budget.
Your pool’s filtration system is incredibly important. Not only does it help keep debris from gathering in your pool, but it also helps ensure proper circulation, which, in turn, helps to keep a proper chemical balance in your pool. All pool pumps, regardless of type, rely on water circulation through some sort of filtration medium as a means to catch debris, pathogens, and any other nasties that may be trying to make their home in your water.
The Three Main Types of Pool Filter
There are three commonly used types of pool filter that we will be discussing in this guide: sand filters, diatomaceous earth (DE) filters, and cartridge filters. Let’s take a look at each type in turn.
Sand Filters
This is the most common type of filter used in both residential and commercial pool systems and is suitable for both above-ground and inground pools. A sand filter is comprised of a large tank that contains special pool-grade sand (it is important to note that not just any sand is suitable for a pool sand filter). Water and debris are pulled through the filter where the debris is removed and the water is then returned through the return jets. This is one of the most cost-effective ways to filter your pool and the maintenance is not a huge investment of time. The filters come with what is called a multiport, which has different settings for vacuuming, filtering, or removing water to waste.
Sand filters do get clogged over time and backwashing them is part and parcel to the proper maintenance of a sand filter. In essence, you are circulating water backward, to waste, through your filter, thus flushing out large chunks of debris and other materials that can clog your filter over time. It is recommended that you do this about once a week, perhaps more often if you notice a decrease in your water pressure, which is often an indication that the filter is clogged and in need of rinsing. Sand filters are effective at removing debris that is as small as 20 microns. With proper care, they can last between 5-7 years before they need repair or to have the sand changed out.
Diatomaceous Earth (DE) Filters
Typically, DE filters are only made for use with inground pools. In many ways, a DE filter works much the same way as a sand filter, just with the use of a different substance for filtration. This type of system uses a substance called diatomaceous earth. DE is a naturally-occurring substance (actually a sedimentary rock) that has been crushed into a fine powder. Like a sand filter, a DE filter is comprised of a large tank but uses what are called “fingers” of DE to line the tank, rather than sand. Water is then pulled through the system where the DE acts to remove debris from the water in much the same way a sand filter does. The biggest difference between a DE and a traditional sand filter is that a DE filter can remove particles that are as small as 5 microns. This makes it much more effective at filtering than a sand filter, but there is also a huge cost difference between sand and DE filters.
Like a sand filter, DE filters will also need to be regularly backwashed to keep it from getting clogged with debris. DE will need to be replaced a lot more regularly than sand, which adds to the cost of this system. Some DE systems utilize a grid. If you choose a grid-based system, you will also need to remove the grid and washed. Cartridges for DE filters generally need to be replaced about every 3 years, depending on pool usage. If you have a really large pool, a DE filter may not be as effective as a sand filter.
Cartridge Filters
This is the most expensive but most convenient type of pool filtration system available. Basically, like an air filter, a cartridge filter system uses filter cartridges which trap debris that is pulled through it. These are pretty effective at removing debris and works well for particles as small as 10 microns, making it more effective at filtering than sand, but less effective than DE filters. A cartridge filter will be more energy-efficient than sand or DE filters, which will make a difference in energy costs, partially offsetting the greater expense of the storm. They also use less water than the other filter types discussed here. Like a DE filter, a cartridge filter works best for smaller pools and are suitable for both in-ground and above-ground pools.
One of the things people like most about cartridge filters is their ease of use. They do not require backwashing and are a low maintenance option for people with smaller pools. With regular use, a cartridge filter will need to be replaced about every 3 years, more often if your pool has a lot of use.
The Verdict: Which is Best?
As with so many things pool-related, the answer is: it depends. The size of your pool can be a determining factor in what type of filtration system you choose. If you have a larger pool, you will likely want to stick with a traditional sand filter. For those with above-ground pools, your choice will be between sand and cartridge filters and the determining factor there may be cost and maintenance requirements.
It also depends on the expectations of your filter. If you are concerned with getting the best filtration, a DE system removes the smallest particles of all the major filtration systems discussed here. The cost can also be a deciding factor. While sand filters do require a bit more maintenance, they do cost less to install and maintain than either DE or cartridge systems. Both sand and DE systems have to be backwashed regularly. With both DE and cartridge systems, you will need to replace the filter or DE about every 3 years, whereas a sand filter typically needs to be changed every 5-7 years.
You will need to consider your pool, your preferences when it comes to maintenance, and your budget to choose the option that will work best for your specific needs.