How Full Should My Pool Sand Filter Be-Changing & Replacing Pool Filter Sand (2021)

Looking for an easier way of changing the sand in your swimming pool’s filter?

Well, then you’ve clicked on the right guide.

The swimming season is perhaps around the corner, and you have probably just noticed that the sand filtration system of your pool is not working optimally.

The water has gotten dirty and cloudy and doesn’t seem to clear up no matter how much sanitizer you use. Then perhaps it is time to clean your filter and replace the sand within.

But you are probably asking yourself, “How to change the sand in a sand filter?” And believe us when we say that changing the sand in a filter is not an easy feat to accomplish, especially without the proper knowledge.

Worry not! Today, we have brought you a guide that will significantly ease out the sand replacement process.

We will go over a step by step list of the proper do’s and don’ts of sand changing in your pool filter.

So, sit back, relax, and let us guide you through.

How to change the sand in a pool filter?

Change pool filter sand

Changing the sand in your pool sand filter can indeed become a challenging task without the proper know how. But if taken as a step by step method, it can significantly simplify the overall process, making it a rather fun DIY activity.

So let’s go over all its significant steps in detail, and determine some of the factors that should be kept in mind while attempting a sand replacement.

Step 1: Prepare to change sand in the pool filter

Any machine part replacement or repair procedure starts off with the right amount of preparations. And by preparations, we mean stocking up on the right supply of materials and equipment that you would require for the job. For sand replacement work, the supplies would usually include sand, an O-ring to separate the valve and tank along with Teflon tape, lubricant, and unions.

When buying the sand, it’s better to get the high-end no.20 Silica Sand, and depending on the filtration system you use, the amount of sand can range from 3.50 lbs bags to 150 lbs.

After you have all your supplies in check, it’s now time to start with the replacement process. But before you begin to change the sand, it’s important to make sure that you turn the pool pump off along with the timer (if it has one). For added safety, you can turn off the pump straight from the circuit breaker itself.

After you switch off the pump, turn the drain cap at the bottom of the filter tank to release the pressure. Turning it half a click counter-clockwise should be enough to let out all the air. Then, when the initial burst of air pressure is out, remove the cap completely to drain out the water that may still be inside the tank.

And finally, disconnect the waste hose that is fixed to the waistline of the Multiport Valve.

Changing pool filter sand Step 2: Removing the Multiport Valve

To be able to change the sand in your filter it is first essential to remove the Multiport Valve. If your filter has unions, then to remove the valve start by unscrewing the attachments that connect the water piping to the pool pump and return ports. For a filter without unions, it’s better to cut out the piping that connects the two ports manually.

If your filter doesn’t have a union installed, then now would be the right time to go about doing it. So make sure that by the time you’re done replacing the sand you leave enough room to attach unions and stagger the cut in such a way that no two unions are installed atop each other.

After the port attachments are off, take out the Multiport Valve flange clamp which securely holds the filter in place. Unscrew the bolts that separate the clamp and with a slow twisting motion lift the valve off the pipe. Make sure you don’t yank at the valve or pull too fast, as the excess force might break the lateral pipes that are situated at the bottom of the tank.  

Replacing sand in pool filter Step 3: Removing the used up Sand and preparing the tank

As soon as you remove the Multiport Valve off the pipe, tape the pipe’s mouth to prevent sand from entering it and clogging the laterals. After you seal the pipe carefully empty out the sandpit with a plastic cup or a wet and dry shop vac until the top of the laterals at the bottom of the tank are visible.  

Slowly rotate the 10 laterals up to the side of the pipe so that they clear the hole, then smoothly pull the pipe and lateral assembly out of the rest of the sand. Notice if there are any breaks in the laterals, replace the ones that look damaged and worn out. And if they appear clogged just soak them in a bucket of cleaning solution for a few hours.

Then thoroughly wash the tank with a garden hose and check the drain cap for any cracks. Replace it if you find any and fill half of the filter tank up with water so that it effectively provides a cushion when you pour the new sand in. Some water in the tank also makes sure that the laterals are protected from getting clogged.

Now put the lateral assembly and pipe back inside the tank, while still making sure that the 10 laterals are rotated up. And after the lateral assembly is secured in, turn the 10 laterals 90 degrees back to their downward position.

How to replace sand in pool filter Step 4: Change Sand in Pool Filter

Any high-end pool filter sand you buy will always come in a cardboard sand shield which you can effortlessly place over the pipe, to seamlessly transfer the new sand in. If by any chance you lack the sand shield, you would need to be more cautious and make sure that the pipe remains centered in the tank at all times while you are pouring in the sand.     

Be very careful while you pour the sand into the pool sand filter. Fill up the tank to the point where the laterals are not visible anymore. Also make sure that you are leveling the sand as you pour, as an uneven sand distribution would completely ruin the filtration cycle and your pool’s water circulation.   

Try not to accidentally lift the pipe and the lateral assembly up off the bottom of the tank. As you won’t be able to push it back down afterward without making the laterals rotate up. Upward facing laterals will not allow your pool sand filter to function appropriately.

Finally, remove the O-ring present at the bottom of the Multiport Valve and check for wear and tear, replace the whole ring if you find any. Lubricate the O-ring with a silicone based lubricant, try not to use too much of it, because an extra greasy O-ring will not be able to function as intended.

Final Steps to changing pool filter sand

Once you’re done replacing sand in the pool filter, it is now time for the final few steps to get your sand filter up and running again.

Begin by removing the tape from the pipe’s mouth and carefully place the Multiport Control Valve back in its original position. Make sure that you set up the valve clamps around the tank and tighten them nicely to secure the Multiport in place. You can even take an additional measure of equipping the screws with a vinyl cap, which will protect them from rust and corrosion.   

Now reconnect the unions with the pool pump and the return ports. If your filter did not have unions attached to it, now would be the right time to do so, or you can just glue the pipes back together with straight couplers.  

After the filter is all set, it’s time to backwash it, so make sure you have your waste-line exiting at the right place, where you want to dump the pool water waste. With the pump still switched off turn the Multiport Valve handle to the backwash position and finally switch on the pump.

Run the pool pump for 2 minutes after the pump is completely primed, and the wastewater flowing out has a steady current. The backwash is necessary to flush out the impurities in the water and the finer sand particles from the sand media.     

When all the suspended particles are flushed out, you will notice that the water coming out of the backwash is significantly clear and clean. Now turn the pool pump off and set the Multiport Valve to rinse followed by turning the pool pump back on again. Wait till the water in the sight glass clears up (shouldn’t take more than a minute) and your pump is good to go.

Enjoy your pool to your heart’s content.

So, how often should you replace sand in your pool filter?

We have gone over all the major steps that should be followed while changing the sand in your filter. But now you might probably be asking, ‘How often to change sand in a pool filter?’

Well, after years of experience with every type of pool filter from cartridge to sand and D.E, we would recommend that you change the sand in your sand filter every 3 to 5 years. But there may be a need to change the sand before that as well, especially when your pool water turns cloudy.

A lack of proper pool water chemistry and sanitization can leave a lot of suspended particles and microbes in your pool unchecked. This will make your sand filter work overtime to clear the water of all the impurities putting excess stress on the sand media. This might lead to your sand filter wearing out and stagnating the water circulation leading to the cloudy pool water.

Under such circumstances along with pool chemical treatment like shock and flocculation, you should replace the sand media as well. Make sure you check the O-ring too, as they are quite often the first to wear out and get damaged.

Is it really necessary to change the sand in your sand filter: The Argument

Against Sand Replacement

There have been some researches that show that the only time one needs to change the sand from their filters is when the sand becomes too heated and gets converted to glass. And this is a process that only occurs in the sand that is more than 50 years old. So as an alternative all you need to do is clean the filter with either an acid or a base, or disinfectants that have Desopur.

A few pool filter specialists have even stated that a sand filter is a permanent media filter and the only reason to throw it away would be when the sand calcifies into solid concrete. And the chances of that occurring in the lifetime of a filter is very low.

For Sand Replacement

A much more popular opinion among sand filter experts. The basic idea behind sand replacement is that even though sand is a permanent filtration media, it is far more affordable to replace it every 3 to 5 years than to clean it.

And depending on the sand you are using, this fact is entirely accurate to a larger extent, as the sand cleaners and disinfectants tend to be very expensive.   

Change sand in pool filter – Conclusion

Ending a day with a quick swim in our pool is a beautiful experience, as pool water tends to act as an amazing stress buster that helps you cool down and relax. But to continue enjoying the benefits of the pool, you will need to maintain it regularly, which is not easy to accomplish, especially when it comes to the filter.

But we hope our guide today was able to cater to your sand filter needs and answered some of your questions like, ”How to replace sand in a pool filter?”

Till next time!