Why Sand is Coming Out of Your Pool Filter and Into the Pool

When you notice sand particles appearing in your pool, it can be alarming and frustrating. There are several possible causes for this issue, and identifying the right one is crucial for maintaining the cleanliness and quality of your pool water. Here, we explore some of the common reasons behind the appearance of sand in your pool filter and provide solutions to fix the problem.

Common Reasons for Sand in a Pool Filter

There are a few likely reasons why sand is coming out of your pool filter and into the pool. Here are the most common ones:

Backwashing: After a backwash cycle, a small amount of sand might 'poof' into the pool due to the high-pressure water displaced by the action. Overfilled Filter Tank: If your filter tank is overfilled with sand, some sand may leak back into the water. Incorrect Sand Size: Using the wrong type or size of sand, such as sand that is not 45-55 mm in size, can cause sand to leak into the pool. Cracked Underdrain: The underdrain, also known as the "laterals" in modern terms, can have a crack or break, causing sand to pass through.

Understanding the Underdrain and Laterals

Every pool filter has a manifold or underdrain that keeps the sand in place while allowing water to pass through. This component is responsible for preventing sand from making its way into the pool water.

If a lateral has broken or cracked, it can allow sand to escape. This can happen to one or more laterals, or the hub and standpipe, which typically connect to the laterals.

Rare but Possible Issues

Although the issues mentioned above are the most common, there are also rare issues that can occur:

Filter Machine Breakdown: Sometimes, a breakdown of the filtration material, such as fiberglass mat or cloth, can cause sand to be pushed into the pool during the backwash cycle. Pump Line Leak: A leak in the return line to the pool can cause sand to be picked up and carried into the pool.

In such cases, you may need to:

Remove the sand from the filter tank. Inspect the components for any signs of damage. Replace any broken laterals or other parts. Insert new sand and dispose of the old sand.

Preventive Measures

To prevent sand from entering your pool, consider the following preventive measures:

Ensure that the filter tank is the correct size and not overfilled with sand. Use the appropriate type and size of sand for your pool filter. Regularly check the underdrain and laterals for any signs of damage or cracks. Have your pool filter checked by a professional if you suspect any issues.

Regular maintenance and attention to the performance of your pool filter can help prevent sand from entering your pool and maintaining its cleanliness.

Conclusion

If you're experiencing sand in your pool filter and it's making its way into the pool, don't panic. There are several potential causes, but with the right steps, you can identify the issue and take action to solve it. Whether it's a broken component, incorrect sand size, or a need for regular maintenance, tackling the problem quickly will keep your pool clear and enjoyable.