Understanding Pool Filters: A Comparison of Sand, Cartridge, and DE Filters

A clean pool is a happy pool, and the key to maintaining that crystal-clear water is having an efficient pool filter. But with so many types of filters on the market, how do you choose the right one for your pool? In this blog post, we’ll break down the mechanics of how pool filters work, comparing the three most common types: sand filters, cartridge filters, and diatomaceous earth (DE) filters.

What Does a Pool Filter Do?

At its core, a pool filter works by trapping dirt, debris, and other impurities that make their way into your pool water. This process ensures that the water remains clear and safe to swim in. Water is pumped from the pool through the filter, which removes particles before sending the clean water back into the pool. The method by which each filter captures impurities differs, which is why you might opt for one type over another depending on your pool’s needs.

Sand Filters: The Simple and Reliable Option

How They Work:
Sand filters are the most common and affordable option for pool filtration. They consist of a large tank filled with special pool-grade sand. Water flows through the sand, which traps particles and debris in the spaces between the grains. Over time, the trapped impurities accumulate in the sand, which is why regular backwashing (a process of reversing the water flow to flush out the trapped debris) is necessary.

Pros:

 

• • Low maintenance costs

• • Easy to operate

• • Lasts a long time

• • Typically lower upfront cost

Cons:

 

• • Less efficient at filtering out very small particles

• • Requires more frequent backwashing, which wastes water

• • Can take longer to clear up cloudy water

Sand filters are great for basic pool maintenance and are typically best suited for pools that aren’t overly prone to heavy debris or fine particles.

Cartridge Filters: The Mid-Range Solution

How They Work:
Cartridge filters use a pleated fabric material (usually polyester) to capture debris. The water passes through the cartridges, and the fabric traps particles as they try to flow through. These filters are housed in a tank that holds one or more cartridges. Unlike sand filters, cartridge filters don’t require backwashing, making them more water-efficient. Instead, you just remove the cartridges and clean them manually.

Pros:

 

• • More efficient at trapping fine debris compared to sand filters

• • No backwashing required

• • Water-saving, since it doesn’t waste water for cleaning

• • Easier to maintain and service

Cons:

 

• • More expensive upfront compared to sand filters

• • Cartridges need to be replaced every few years

• • Requires periodic manual cleaning

Cartridge filters offer a good balance between performance and ease of use, and they’re ideal for pools that require more detailed filtration but where water waste is a concern.

DE Filters: The Premium Filtration Solution

How They Work:
Diatomaceous earth (DE) filters are the most efficient type of pool filter. DE is a powder made from fossilized remains of diatoms, which are microscopic aquatic organisms. When the water passes through the filter, DE coats a grid inside the filter tank, creating a fine filtration surface. This method captures the tiniest particles, making DE filters capable of filtering out contaminants as small as 2 to 5 microns (for comparison, human hair is around 50 microns thick).

Pros:

 

• • Extremely high filtration efficiency

• • Removes very fine particles, making water clearer than other filter types

• • Ideal for pools with high bather loads or high debris

Cons:

 

• • Higher upfront and maintenance costs

• • Requires regular backwashing, plus adding more DE powder

• • More complex to maintain compared to sand and cartridge filters

If you want the clearest water possible and are willing to invest in more intensive maintenance, a DE filter is the way to go. It’s especially great for pools with high use or heavy debris.

Final Thoughts: Choosing the Right Pool Filter for You

When selecting a pool filter, consider factors like the size of your pool, how much debris it collects, your maintenance preferences, and your budget. Here’s a quick guide to help you decide:

 

• • Go with a sand filter if you’re looking for a simple, cost-effective option and don’t mind more frequent backwashing.

• • Choose a cartridge filter if you want better filtration efficiency, easier maintenance, and water savings.

• • Opt for a DE filter if you want the highest level of filtration and are prepared for a higher maintenance commitment.

Whichever type you choose, remember that regular maintenance, such as cleaning or replacing the filter, is essential to keeping your pool water clean and healthy.

Have questions about what is the right filter for your needs? Our team of experts are more than happy to help!