Sand Pool Filter Troubleshooting and Maintenance

Written by Michael Dean
March 4, 2024

troubleshooting a sand pool filter

Sand filters are one of the most common filter types. The sharp particles of specialized sand catch debris that flows through the filter and cleans the pool water. Sand filters are generally pretty reliable but are not immune to issues. So, knowing how to identify and fix these issues can come in handy.

In this article, I will discuss some common issues with sand filters and some helpful maintenance tips.

Main Takeaways

  • Some common sand filter problems include sand leaking into the water, high/low filter pressure, dirt in the water, leaking sand filter, and loose/broken multiport handle.
  • You should replace your sand every 3-5 years and your entire filter system every 2-3 decades.
  • To keep your sand filter running optimally, change your sand when needed, clean and backwash the filter often, and don’t skimp on sand.

Common Sand Filter Problems

In this section, I will review how to troubleshoot different sand filter issues.

Sand Leaking into the Pool Water

Finding small amounts of filter media in the pool water with DE and sand filters is not uncommon. When changing the sand or backwashing, you may notice bits of sand have made their way into the pool. This usually isn’t a problem as long as the amount of sand is minimal.

If you notice unusual amounts of sand collecting in the pool, a more significant issue may be at play. Old filters may have worn down, or parts may be broken, so you will likely need to take the filter apart and examine all the components.

Causes and Solutions for Sand Leaks

The first step in fixing this issue is determining the cause of your filter blowing out sand.

Broken Lateral or Standpipe

The main reason your sand filter leaks sand into the water is broken parts such as the lateral or standpipe. If your standpipe and/or lateral are broken, you will notice large amounts of sand leaking into the pool. To fix this, purchase new parts, remove all the sand from the filter tank, and replace the broken parts.

Damaged Backwash Valve

Your backwash valve may also be causing this problem. If there is a leak or issue with the sealing in the backwash valve, small amounts of sand could leak into the return pipe and make its way to the pool when you backwash. This is usually a relatively easy fix, as you will only need to replace the O-ring for the valve. On the other hand, you will need to replace the entire valve if you have a more heavily damaged backwash valve.

High Filter Pressure

High filter pressure is an issue all pool owners will run into at some point, and it is not usually something to worry about. Depending on the specific sand filter model, you should expect to keep your filter pressure at 5-20 psi. Check the manufacturer’s instructions for the optimal range.

If your filter pressure goes too far over the recommended range, you risk a burst filter, which can be very dangerous. This is why staying on top of your filter maintenance is very important.

Causes and Solutions of High Filter Pressure

Here are some of the common causes of high filter pressure.

Dirty Pool Filter

The majority of the time, high filter pressure affecting your sand filter is due to a dirty filter. The filter pressure builds as the sand particles catch algae and other debris. This can be fixed by simply cleaning out your filter and backwashing. However, if the backwash time is getting short, it’s possible that it’s time to change out the sand. Remember: you should get new sand for your filter every 5 years.

Overfilling Sand

Another reason for high filter pressure is too much sand in your filter. It is important to learn the correct quantities when filling your sand filter or risk sand overflowing into your pool water. Read my guide on filling your sand filter for more info.

Pump Too Strong for Filter

If the pressure in your sand filter is still too high, your pump may be too strong for your sand filter. In sand filters, this can cause an issue called channeling, where water will create a path, or channel, that is easier to get through rather than properly filtering through the filter media. To fix this, if you have a variable speed pump, run it at a low speed. Otherwise, you’ll need to get a new pump entirely.

Clogged Return Pipe

The final cause for high filter pressure is clogged return pipes. Due to the constant flow of debris from the pool water into the pool filter, your plumbing can eventually become clogged. If this happens, less water can escape the filter, and the pressure inside will build up.

Fixing this issue likely involves taking the filter apart. It may be possible to unclog the pipes by placing a hose in the piping and pushing high-pressure water into the clogged area. But more likely than not, you will need to take apart the system to unclog it.

Low Filter Pressure

Low filter pressure is less common and less dangerous than high filter pressure. But that doesn’t mean it isn’t important to fix it. Low filter pressure means water is not flowing through your filter at an acceptable rate, so the pool water is not getting cleaned properly.

Causes and Solutions of Low Filter Pressure

Here are some common causes (and their fixes!) of low filter pressure.

Clogged Skimmer Basket

The most common reason for lower filter pressure is a full skimmer basket. If you notice your filter pressure is low even after the pool pump is turned on, check your skimmer basket. If the skimmer is full of debris, empty it, and you will likely see the filter pressure return to normal.

Clog in the Plumbing Before the Filter

If the skimmer basket is empty, but the filter pressure is still well below average, your culprit is likely a clog in the plumbing. For the pressure to be low, the clog will have to be before the filtration system. You will likely need to take apart the plumbing to clear any blockages to fix this.

Air Leak

If an air leak is the issue, it is a bit tedious to fix, but it is still possible to do it yourself. Signs of air leaks in your filter are bubbles coming out of your return line or in the strainer pot of your filter system.

There are several ways to fix an air leak, but it usually involves filling the pool water more, replacing a damaged O-ring, or replacing old broken plumbing components. Contact a pool professional for assistance if you cannot fix the issue yourself.

Dirt in the Water

On a similar note, an issue sand filter pool owners may come across with their filter is the sand filter simply not filtering the water as it should. Even if the filter is turned on and seems to do the work, are you noticing dirt in your pool water? In this case, it’s likely an issue with the sand filter media itself or the laterals.

Causes and Solutions of Dirt in the Water

If you’re finding dirt in the water of your sand filter pool, don’t worry; it is likely relatively easy to fix.

Old Sand

One of the main reasons your sand filter is not filtering the dirt in the pool properly is because the sand is old. Sand filter media should be replaced every 3 to 5 years. If it’s been more than 3 to 5 years, it’s time to change out the sand.

Clogged Sand

If it’s not yet time to change out the sand of your filter, it may simply be time to backwash your pool filter. Over time, your sand filter may become clogged with dirt and debris, which can reduce efficiency. As good practice, backwash your sand filter every 2 weeks.

Too Much Debris

Your sand filter shouldn’t be the only one doing the work to clean your pool. You should also roll up your sleeves to clean the pool by skimming, brushing, and vacuuming often. If you don’t, too much debris might end up in your pool, causing your filter to work that much harder to keep your pool clean. Worse, there might be too much debris for your filter to handle.

Dirty Laterals

If dirt and debris are being blown back into the pool, it’s possible that your laterals may be dirty and clogged. To fix this, remove them and soak them in a bucket of water and a mild cleaning solution.

Leaking Sand Filter

When inspecting your sand filter, are you noticing a leak? A leaking sand filter can range from minor issues that can be DIY’d to more major issues that may require you to replace the entire filter altogether. When troubleshooting a leaking sand filter, it’s important to take a close look at the filter to determine exactly where the filter is leaking.

Causes and Solutions of Leaking Sand Filter

There are two main causes for a leaking sand filter: a faulty gasket or O-ring or a cracked tank.

Faulty Gasket or O-Ring

Generally, if you spot a leak from your sand filter, you are dealing with a fault gasket or O-ring. If this is the case, the sand filter is likely leaking from the top. Check the spider gasket and O-rings for any wear and tear. Recalibrate the gasket and/or lubricate the O-rings, but if needed, replace the parts.

Cracked Tank

If the leaking is occurring from the filter tank itself, unfortunately, it might be time to replace the entire sand filter. While you can buy a tank for your filter separately, this generally costs more than replacing the sand filter as a whole.

Loose or Broken Multiport Handle

A final common issue you may come across with your sand filter is a broken multiport handle. The multiport handle has many pathways for the pool water to flow; too much force (or some other external factor) can cause the handle to become loose or broken.

Causes and Solutions of Loose or Broken Multiport Handle

Here’s why you may have a loose or broken multiport handle and how to fix it

Loose Multiport Handle

If the multiport handle is loose, it may be wiggly due to a loose or broken spring in the system. To fix this, access the spring by unscrewing the lid to get to the assembly within. Then, take out the spring and replace it with a new one. At this point, you should check any O-rings and lubricate/replace them as needed.

Broken Multiport Handle

There is no one overarching reason why your multiport handle might be broken, but generally, the reason is too much force being used to open it. Or perhaps something might have hit it during a severe storm. Whatever the reason, here’s the good news: fixing a broken multiport handle is as easy as replacing it with a new one.

How to Know It’s Time to Replace Your Sand Filter System

Sand filter systems can last a very long time if maintained properly. But, inevitably, they will eventually need to be replaced. You should expect your sand filter to last 2-3 decades if you keep a consistent cleaning schedule. Over time, your tank, plumbing, and pump will start to collect mineral deposits and wear down. Individual parts can be replaced, but there comes a time when there is nothing you can do but purchase a new filter altogether.

There is no rule for when you will need to purchase an entirely new pool filter system. The choice is really up to you to weigh the pros, cons, and cost benefits of investing in a new system. If you feel like you need a new system, check out my recommendations for the best pool filter.

Sand Pool Filter Maintenance Tips to Keep It Running Well

Here are my final tips and tricks for keeping your sand pool filter running optimally.

Change Your Sand When Needed

Many pool owners sleep on this, but it is extremely important to change your filter sand every 3-5 years, or when the filter sand shows signs that it is no longer effective. Some common signs that your pool’s filter sand needs to be changed are:

  • It has been 3-5 years since you changed the pool sand
  • Cloudy, dirty pool water
  • Clusters of sand forming in your filter
  • Water creating channels in the sand

You can read my guide on how to change your pool filter sand to learn how to do it.

Backwash and Clean Your Filter Consistently

I recommend that you backwash your sand filter at least every 2 weeks. However, on top of that, you should also deep clean the filter 2-3 times a year. For this, I usually drain the filter and thoroughly rinse the sand and filter tank until the water comes out clear. Sometimes, simply backwashing isn’t enough, which is necessary to prolong the life of your filter sand.

Don’t Skimp on the Sand

There are hundreds of pool sand products on the market, so I can understand how overwhelming it can be to choose one that works best for your system. Talk to a pool professional at your local pool store to get advice on the best sand for your specific system. But in general, I highly recommend purchasing silica sand. It is the best-performing, longest-lasting, and most efficient option on the market. It costs more than other products, but you get what you pay for.

Troubleshooting Sand Filter Brands

While a general guide like this can be a lot of help, sometimes, you may come across a brand- or model-specific issue. To help with this, it’s best to have access to the official help guides. Brands know the common issues that pool owners may come across with their specific sand filters, so these guides can be excellent resources for troubleshooting as well.

Here are the most popular sand filter brands and their troubleshooting guides:

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Sand Troubles No More

Sand pool filters can run into a few problems during their lifetime, but they are pretty easy to troubleshoot and fix most of the time if you know what to look for. Check out my guide with more troubleshooting tips for every type of filter if your pool filter is still not working.

Still experiencing issues with your sand filter? Feel free to reach out to me. I am always happy to help!

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