When and why change pool filtration sand?

Do you want your pool water to be of optimal quality all summer long? Want to know how to properly maintain your filter to get there? You’re in the right place!
Pool filters work thanks to different filtration media, like sand and glass. To maximize the life of your filter and the quality of your water, you must use the right medium and replace it at the right frequency. 

Our experts have tackled the matter to answer all your questions!

Why is filtration sand so important?

To the naked eye, the sand you put in a pool filter may appear fairly uniform. However, each grain of sand has a rough texture that allows it to retain fine particles that wander into your pool water. This is how the sand purifies the water and prevents any contaminants from getting through.

Why change the sand in your pool filter?

Filtration sand captures impurities present in the water, but over time it loses its effectiveness for different reasons:

Debris Accumulation: Captured particles and debris eventually clog the sand and reduce its effectiveness.

Natural wear: Over the years, the back and forth movement of water over the sand makes it smoother and smoother, and therefore less and less effective at trapping all those little unwanted particles. 

Bacteria Growth: Bacteria can build up and create microorganisms that affect water quality.

In short, if you never change the sand in your pool filter and it can no longer do its job properly, water quality will be greatly reduced (growth of algae, presence of bacteria, etc.). 

Lime scale: a common problem in sand filters

With time, a small amount of limestone clings to the sand grains and accumulates. This causes the sand grains to clump together and become hard and compact. 

These sand “clusters” affect filtration quality. In the worst-case scenario, all of the sand in the filter can become one big petrified block and not be effective at all. Regular backwashing and maintenance of the filter and sand with specially designed products are usually sufficient to avoid these problems. 

When should you change the filtration sand?

No matter what type of sand you use, it must be changed to keep the filter working properly to remove contaminants from pool water. 

In general, it is recommended to replace sand every 3 to 5 years.  However, several signs may indicate the need for sooner change:

A few signs can help you know that it’s time to make the change:

• Compact (sometimes viscous) sand clusters form in the filter.
• Pool water does not stay clear and clean.
• Sand accumulates at the bottom of the pool.
• You must run the pump longer or use more product to maintain water clarity.
• You have more problems with algae than before.
• A drop in pressure in the filter. If the pressure in the filter is consistently low despite regular backwashing, the sand is probably clogged.
• Constantly green water indicates that the filter is no longer doing its job correctly.

You can also assess the quality of the sand by handling it with your hand:

• If the sand flows smoothly through your fingers, it is still good.
• If the sand slides with difficulty between your fingers and forms clumps, it means it needs to be changed.Compact (sometimes viscous) sand clusters form in the filter.

Can the service life of filtration sand be improved?

Although filtration sand will eventually need to be replaced, proper maintenance of the filter and sand can extend its life, sometimes up to 6 or 7 years. How? With regular backwashing and one or two sand cleanings per summer with specially designed products! Note that you will still need to adjust the amount of sand about every two years. 

It is also recommended to use a descaler (to fight limescale), once at the beginning or end of the season and again in midsummer.

Is it possible to use filtration glass in a sand filter?

More and more people are turning to filtration glass as a clean and cost-effective long-term alternative to sand. In fact, here’s how to make the right choice of filtration media for your pool.

The answer to this question is simple: yes, it’s possible! The only thing to remember is that you will need to put about 20% less glass than you put sand into the filtration system. This is because glass is denser than sand and therefore less is needed. We are talking about 50 lb for sand and 42 lb for glass. 

Glass meets all of the pool filter manufacturer’s standards and will not cause any problems with warranties. 

Change the filtration sand when the time comes.

Now you know when to change the sand in your pool filter and why it is important. Changing the sand in a pool filter is an operation that can usually be done in one day with a few common tools. Follow the instructions of your pool filter manufacturer or contact an expert to help you choose your filtration product!