Knowing how to change pool filter sand is easy and you don’t do it often but the process is messy and time-consuming especially for a first-time pool owner.
You could simply hire a pool maintenance contractor to perform the task, however, this is definitely a job that anyone can perform themselves to save money.
First you need to learn a few things. You need to know when to change the sand, what type of sand to use, how to open your filter tank, how to replace worn filter parts and how to reassemble everything again.
Table of Contents
What is Pool Filter Sand?
Sand is a natural filter medium used by nature to purify water in streams and rivers.
Pool filters use sand as the filter medium to remove and capture dirt and contaminants from pool water. Sand is also used in water treatment stations and septic tank applications to remove contaminants from water.
Important: Only use Pool Filter Sand!
Please don’t be tempted to add any sand into your pool filter as it won’t work properly and may damage the filter.
Pool filter sand is either glass, silica or zeolite sand.
Silica Sand
Silica sand is the most common type of pool filter sand and is available in hardware stores, pool shops and online if you want to pay the freight cost. This sand is mined and refined from ground quartz to create sharp, jagged edges that capture contaminant particles in the filter.
Glass Sand
Glass sand is manufactured from recycled glass products into a highly refined filter media.
The product contains grains of glass of slightly differing sizes which you will not be able to see. These differing sizes of grains help prevent water channeling through the sand to the bottom of the filter tank without being filtered. Channeling is a common problem of standard sand filters. For this reason, many people prefer cartridge filters where channelling cannot occur and filter down to a lower micro level.
Glass sand particles carry a slight negative charge which bond with positively charged iron and manganese ions. This helps to remove these metal ions from your pool without using additional chemicals or changing the pool water.
If you want to make a low environmental footprint and encourage recycling this is the product of choice.
Zeolite Sand
This product is refined from zeolite volcanic rock which is very porous with microscopic holes useful to trap dirt and contaminants.
The manufacturers claim zeolite sand can even capture chloramines which are the by-products of chlorine working in the pool to kill bacteria. When a pool has that chlorine or bleach smell it’s the smell of chloramines. This indicates that there is not enough chlorine to sanitize the pool properly and you need to shock treat the pool more frequently.
If you want to be more environmentally friendly and use less pool chemicals try zeolite sand in your filter. You shouldn’t need to shock the pool as frequently and with a lower amount of shock.
Why Change Your Pool Filter Sand?
Pool filter sand has rough, jagged surfaces that capture contaminant particles. This acts like a fine filter sieve like a cartridge pool filter.
Sand filters can be backwashed to clean the sand and release the contaminants into the drain. However, cartridge filters cannot be backwashed and must be manually hosed clean.
Eventually the water makes the sand particles become smooth and round like a pebble in a stream. The sharp edges wear down, reducing the dirt holding capacity of the sand. The filter media has reached it useful life and you need to change your pool filter sand.
There are other issues that cause sand to lose its filtering capacity.
If you have hard water in the pool this can cause calcification of the sand into hard sand balls that are ineffective as a filter media.
Over time oil collects in the sand resulting in gooey oily balls that reduce the effectiveness of the filter media.
When to Change the Pool Filter Sand
Once the pool filter sand has begun to lose its contaminant holding ability it’s time to replace the sand. Otherwise, your pool water will gradually become dirty.
Backwashing the sand will no longer enhance its cleaning capacity.
You will find that you need to run the filter for longer and add more chemicals to keep the pool clean.
I recommend to change your pool filter sand every 3 to 5 years.
How to Change Pool Filter Sand
Follow the process below to replace the sand in your filter.
1. Switch off the pump motor at the power supply
Completely switch off the pump and timer. You don’t want the pump to automatically start when you have the filter disconnected from the water pipes. If the motor started it could rev up and burn out. Water would be sprayed everywhere out of your inlet plumbing pipes.
2. Drain the Tank
Open the drain valve (or plug) at the bottom of the filter tank to drain all the water from the tank. This process can take a while as the sand holds on to the water.
3. Disconnect the plumbing pipes at the multiport valve
Carefully remove the inlet and outlet plumbing pipes connected to the multiport valve. Usually, the pipes have screw fittings so it’s easy to unscrew the plastic fitting and remove the pipe. If the fitting is too tight to unscrew by hand place a rag over the fitting and use a wrench to gently loosen the fitting. Remember to turn the fitting anti-clockwise to open it.
4. Remove the multiport valve from the top of the tank
Most models of sand filter have a collar clamp securing the valve to the top of the tank.
Use a screw driver to loosen the clamp and remove the valve in an upwards motion.
Gently twist and pull upwards on the valve to remove it from the standpipe inside the tank. Don’t pull up on the standpipe because it’s connected to laterals in the bottom of the tank which can easily break off.
5. Cover the Top of the Standpipe
The standpipe is the open vertical pipe inside the tank that connects on to the multiport valve.
Unless you are replacing the standpipe and laterals, cover the pipe opening to prevent sand getting into the pipe. Any sand in the pipe will be blown into your pool when the pump is turned back on.
6. Remove the sand
Remove the sand from the filter tank.
Many pool owners use a plastic cup to scoop out the sand. This is an acceptable method if you have a spare hour or two and strong arms.
The best way to remove the sand is to vacuum it out with a wet and dry vacuum cleaner.
Sometimes it’s easier to turn the tank on its side (if possible) and remove the sand with your hands or Shop-Vac suction cleaner.
When there isn’t much sand left in the tank you can put in the garden hose and wash the remaining sand out the drain at the bottom of the tank.
7. Remove the standpipe and laterals.
If you are replacing the standpipe and laterals remove the fitting from the tank. It can be difficult to remove through the narrow top hole of the tank. You will need to fold the laterals upwards or unscrew them from the standpipe before trying the remove the fitting.
8. Hose out the tank to remove all traces of dirt and old sand.
Give the inside of the tank a good wash with the garden hose to remove all traces of dirt and old sand. The water will run out the drain at the bottom of the tank.
9. Replace the standpipe and laterals.
If you have noticed sand at the bottom of your pool which has been blown in from the filter then you most likely have faulty laterals. Sand is leaking into the laterals and being washed back to the pool.
Please read our article on Why Do I Have Sand in My Pool?
Replacing the standpipe and laterals is very easy now that the tank is empty. Simply insert the new fitting into the tank. Some models have fold down laterals, others have screw on laterals. If the laterals screw on you will need to do this inside the tank. Unless you have a tank that opens in the middle which makes everything much easier.
I recommend replacing the standpipe and laterals every second time you change your sand as these parts frequently wear down and leak.
10. Add some water to the tank
Replace the drain plug or close the valve at the bottom of the tank.
Fill the tank with about one third to one half water to protect the laterals from heavy sand falling into the tank. The sand will hit the water and spread around the tank more evenly.
11. Add Sand to the Tank
Open a corner of a bag of sand and start to slowly pour the sand into the tank.
Always start slowly as the sand has a long way to fall to the bottom of the tank and can damage the laterals. Once you have covered the laterals you can speed up the rate of pouring sand into the tank.
As bags of sand are heavy, some people prefer to pour the bagged sand into a bucket first to make it easier to pour into the filter tank.
I recommend you wear a mask and gloves to protect yourself from the sand dust. Breathing in silica dust is known to cause cancer.
Try to avoid pouring the sand on to the standpipe (which you have taped up).
Don’t over fill the sand. There must be a 6-inch (15cm) gap between the top of the tank and the sand for the filter to operate effectively.
Important: Only use Pool Filter Sand!
12. Fill the tank with water
After you have added all the sand, fill the tank to the top with water.
13. Check the multiport valve gasket
Always check the multiport valve gasket for wear and tear. If the gasket is worn it will leak so replace it now.
I recommend replacing these gaskets every second change of sand.
14. Replace the multiport valve
Remove the protective tape over the top of the standpipe.
Push the multiport valve down onto the standpipe until it sits firmly on the tank collar.
Replace the collar clamp and screws.
15. Reconnect the pipes to the multiport valve
Connect the inlet and outlet plumbing pipes to the multiport valve. Wind the fastening fittings in a clockwise direction to securely connect the fittings with a water-tight seal.
16. Backwash the filter
Turn the multiport valve to ‘backwash’.
Prime the pump with water and switch on the power supply.
Backwash for a few minutes to remove the fine sand dust from the new sand.
Switch off the pump and move the valve to ‘rinse’.
Run the pump for a few minutes to rinse the sand.
Check for water leaks around the tank to ensure all connections are water-tight.
17. Operate the Filter
Switch off the pump and move the valve to ‘filter’.
Activate the pump and check the reading on the pressure gauge. Take a note of the reading as this is you low pressure ‘clean’ reading.
Please read our article on Pool Filter Pressure Gauges
What to Do with Old Pool Filter Sand?
After pool owners change the pool filter sand they ask the question ‘what do I do with the old sand?’
Be careful how you dispose of the old sand.
The old pool filter sand is full of contaminants and is not safe for children to play in.
It may pose a health risk to your family and pets as the sand is made from silica and the dust is known to cause cancer.
Do
- Spread the sand over your lawn or garden bed and water it in.
- Use underneath pavers as bedding sand.
- Use as drainage sand around underground pipes.
- Bury the sand in your backyard.
- Bag the sand and take it to a dump.
- Spread the sand in a forest or bushland area.
Don’t
- Empty the sand into your garbage bin. It’s too heavy.
- Flush the sand down your storm water drain. It may block the drain.
- Use the sand in a child’s sand box.
- Use in your pet’s litter box.
- Add to concrete as pool filter sand is crushed silica which is not strong enough to make concrete. Concrete sand is made with crushed granite and limestone.
Filter Balls for Sand Filter
When you need to change your pool filter sand, you may as well replace the sand with filter balls. This is the modern upgrade for filter sand.
The advantages of Filter Balls
- Much lighter and easier to handle than heavy wet sand.
- Easier than trying to change pool filter sand.
- Easy to fill and empty the filter tank.
- Easy to dispose of in the garbage.
- Clean & recycle your filter balls by washing them in the washing machine.
- Captures finer particles than sand (down to 10 microns) leaving the water crystal clear.
- Filter operates at lower pressure as water can more easily move through the filter balls than through sand.
- The pressure gauge remains low for longer resulting in less requirement to backwash the filter.
- Reduces water usage with less backwashing.
- Results in higher flow rate with strong water pressure stream at the return jets.
- Better water circulation around the pool.
- Vacuum suction pressure is strong.
- Less strain on the pump motor resulting in less filter and pump noise.
- Less strain on the whole filtration system.
- Operate the filter less hours resulting in electricity savings.
- Much less likely to have a broken standpipe and laterals with filter balls as they are not heavy and dense like sand.
- Easier to prepare your filter for winter. Water drains from the tank quickly and it’s easy to remove the filter balls. No more damp sand freezing and expanding in the filter tank causing damage.
- Easy to purchase online and have delivered as there is no weight.
- Filter balls cost less than bags of sand.
Another added use for filter balls is to drop half a dozen balls into the skimmer basket to capture dirt particles before they reach the filter. And it’s dead easy to remove them, give them a rinse and put them back in the skimmer. This works almost as well as a skimmer basket filter sock.
The negatives of Filter Balls
- There are no negatives of using filter balls. It’s like changing an old incandescent light bulb to a LED bulb. The result is better and you’ll save money.