How to Change The Sand in a Pool Filter
A buddy and I changed the sand in his sand filter. He moved into the house about a year ago and was told that the sand was never replaced in a 6-year-old Pentair Sand Dollar filter .
Over time, the sand inside the filter loses its coarseness and becomes smooth and round. This makes it very hard for the sand to catch really small debris particles.
Sand is like a fine wine, it gets better with age, but then has its peak and it’s all downhill from there. Unlike wine, this time period is very short. Every 3 to 5 years you should change the sand in a pool filter.
NOTE: This is very easy to do. Just follow the directions and you will save yourself some money.
What You’ll Need
- Pool filter sand or filter sand substitute (check your filter’s manual for the amount)
- Duct tape or rubber plug
1. Turn Off The Pump And Drain The Filter
Turn off the filter and pump and make sure your timer isn’t set to turn back on. You don’t want the pump to kick on while you have everything disconnected. If the pump runs dry, it can burn out.
Remove the drain plug from the bottom of the filter tank and let all the water drain out. This may take a while, so you can do this ahead of time.
2. Remove The Multiport Valve
Remove the hoses or pipes that are connected to your valve. If your valve is hard plumbed with PVC pipe, you will have to cut the pipe and install union fittings so that you can easily change the sand from here on out.
Remove the clamp or collar that holds the valve to the tank. You may need your screwdriver for this task.
Once the collar and pipes or hoses are removed and disconnected, gently twist and pull up on the multiport valve to remove it.
NOTE: The valve is attached to a standpipe that runs into the sand. At the bottom of the standpipe, there are laterals that spread out along the bottom. Try not to twist too hard, because the laterals could break under the weight of the sand.
3. Cover The Standpipe
Inside you’ll see the standpipe that leads down into a large pile of old filter sand. Before you remove and add the new sand, you need to cover the top of the pipe. You don’t want sand getting inside the pipe, because when you finally finish and turn it on, that sand will end up in your swimming pool.
4. Remove The Sand
Remove all the sand by using your Shop-Vac or a large cup and scoop out all the filter sand.
5. Rinse Out The Tank and Laterals
Now you should see that the filter standpipe has a number of laterals sticking out of it. Use your hose and rinse out the rest of the filter sand.
Take this time to check the pipe and laterals for any cracks or other damages. If the pipe or laterals are broken or cracked, replace them right away before adding the new sand. Broken and cracked laterals will cause sand to end up in your pool.
6. Fill The Tank Halfway With Water
Before you add the new sand to the filter, set the standpipe and laterals in place and centered, replace the drain plug on the tank, and fill it halfway full of water. This will cushion the fall of the sand onto the laterals which will protect them from breaking.
7. Add The New Sand
Remember, you are working with heavy bags of sand. I suggest to place one bag at a time upright near the top and cut the bag open, letting the sand slowly pour into the filter.
Depending on the size of your filter tank, you may have to do this several times. Remember, just take your time to prevent sand from spilling everywhere. And make sure that standpipe is covered.
NOTE: Only use pool filter sand ! There are different types of sand out there including bar sand and play sand, but only your local pool company offers the correct coarse filter sand or filter sand substitute .
8. Fill The Tank With Water To The Top
Once all of the sand is in your filter, fill the rest of the filter up with water. Replace the multiport valve, collar, and pipes or hoses securely and tight.
9. Backwash and Rinse The Filter
Before you turn your filter and pump on, turn your multiport valve to Backwash. Prime your pump and turn it on. Let the filter backwash for at least 2 minutes or until the sight glass is running clear. This will help to get out all of the sand dust and extra debris in the new sand. I recommend using a backwash hose here.
Afterwards, shut off your pump, turn your multiport valve to Rinse, and turn your pump back on. Rinse the filter for about 1 minute.
10. Run The Filter
Great! You are all finished. Shut off your pump, turn it to Filter, and turn your pump back on.
Check the pressure gauge. Whatever the gauge says should be your normal running pressure. Keep an eye on this. When the pressure goes to about 10 psi over the normal running pressure, you need to backwash the filter.
Over backwashing gets rid of the dirt and debris that will actually help pick up new, smaller debris particles. Don’t over backwash. Use the pressure gauge as your backwash indicator.
The Case AGAINST Changing The Sand In Your Filter
In all my years in the pool industry, I have never heard this, but I was interested to learn more about why these folks believed that pool filter sand never needs to be replaced.
Dennis Ashworth of SP&S Swimming Pool & Spa Equipment in Toronto, Canada wrote:
The only thing that will change filter sand is heat when sand is converted to glass. We have worked on filters where the sand is over 50 years old. They must be cleaned with either an acid or a base, or disinfected with Desopur. A sand filter is a permanent media filter. The only reason to throw the filter away would be after the sand calcifies into a solid block of concrete. The industry has spent 40 years telling the professional industry that sand is forever. Sand media is forever and you never have to change it.
Lynn Huso, the National Sales Director of Technical Pool Solutions (TPS) agrees:
… sand media should and can last much longer that what has been the standard. It starts with cleaning. We at TPS have tested new sand at 2.9%, used pool sand at 5%–31% and have arrived at less than 1% calcium in the sand after cleaning with TPS Professional Sand Cleaner.
The Case FOR Changing The Sand In Your Filter
Another member of the group, Chris Baugh, stated that, “It’s almost always less expensive to replace the sand than it is to clean it.”
When we shot that video, my buddy Dave paid about $8 for a 50 pound bag of sand , and we needed 7 bags to fill it. That’s $56 to replace the sand every 3 to 5 years, according to what I’ve always been told in the pool industry.
Note: Prices have gone up since this article was originally written. Still, the cost of replacing sand will be spread out over 3 to 5 years and will vary depending on the cost per bag, and how many bags you need.
Cleaning Your Sand Filter
On top of replacing the sand, I would still recommend cleaning it too. You can buy a bottle of sand filter cleaner for around $20 bucks and do this once a year, so I don’t see how replacing the sand is less expensive.
I went to Hayward Pool Products, a popular brand of sand filters, to see what they suggest …
On average, sand should be replaced every 3–5 years. The jagged edges of the sand wear down and become smooth as the sand ages. When this happens the sand can no longer trap debris particles and dirt can pass through the sand and back into the pool. As the sand ages, it may start to clump and the water flow can form channels in the sand, allowing the debris to pass through.
I even turned to my friends at InTheSwim.com, who wrote an article on changing the filter sand, they said:
Most manufacturers recommend that you change your filter sand about every 5–7 years. “Why do I need change the sand at all?” you ask? Well, over time as water rushes through the filter, the jagged edges of the sand which help to trap debris wear down and become smooth.
It seems as though most manufacturers of sand filters agree that you should change the sand in your filter after a certain number of years. These companies don’t sell sand, they sell filters, so do they really have a reason to tell you to change the sand if it wasn’t true?
However, don’t you think these companies should make it easier to change the filter sand if you ARE supposed to change the sand every few years?
Should I Replace My Pool Filter Sand Or Not?
After reading all of these comments and a bunch of online articles about the subject, I’m going to continue to recommend pool owners to change the sand in their filters every 3 to 5 years.
Personally, I would change the sand every 5 years. It doesn’t take too long to do it, and it gives you a chance to get outside and learn a little bit more about your swimming pool, and I’m all for that.
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