When To Change Pool Filter Sand

If my swimming pool shows signs of cloudy water, constant high pressure on the sand Filter’s gauge, even after backwashing. Could it be the sand media in my pool filter? How long does sand media last?  When do I change the pool filter sand?

On average, sand should be replaced every 3-5 years. This may be longer if the pool has less use, is well managed, chemically balanced, & is clear.
Shorter if the pool gets a lot of use, is not properly maintained, & the H2O is not chemically balanced making the Sand filter work longer & harder.

Keeping a well-maintained swimming pool will save you money over the course of the season. If your pool water chemistry is on target and the mechanical part of your system is performing up to par then all signs lead to taking a look at the sand. When should you change the pool filter sand?


When to Change Pool Filter Sand



                                                   Sand Filter


If your pool is chemically stable and still is not producing clean clear water the problem is most likely in your pool filter. Most high-rate sand filter is really efficient and works exceptionally well. The sand particles are ground to the consistency of .45 to .55 in diameter rough enough to trap debris, but fine enough to allow water to filter through.

If the sand filter and pump are sized well, according to the manufacturer’s specification, it’s most likely the sand in the vessel that needs to clean or change. The time to do this is before the season starts. You will spend less time at the Pool store spending money that you don’t have, buying products you don’t need to fix problems that could have been prevented.

Swimming pool Sand as a filtering media is a reliable method that lasts a long time and as long as your pool has fairly normal use and you are not backwashing too long or cycling too much it should last a long time.

As reliable as silica sand can be it has limitations as a filter media.  Anything in the water that is smaller than 30- 40 microns will most likely not be filtered by the sand. The cleansed water is returned to the pool through a set of lateral tubes at the base of the filter.

To kill bacteria and algae you need to add pool chemicals to the filtered water, but the sand pool filter will reduce the need for harsh chemicals. Filtration is an important part of the treatment of your swimming pool.

Always make sure that the pool water chemistry is not the problem. You don’t want to pull the lid off the filter before checking off the easier things to fix. Make sure you are following the instructions in your owner’s manual. Always ask if you are not sure and the person you ask should be the person who built the Sand Filter. The sand bed may be clogged with mineral deposits or other materials that will not backwash away.

Some calcium-based chlorines and other alternative sanitizers could cause a build-up in the filter’s sand. You may need to swap the sand. or at the very least change some of the sand and add an additive that will help dissolve the hard contaminants that are clogging it.


How Long Does pool filter sand Last


Eliminate other problems that may be happening in your pool first. Then check these symptoms:


  1.  The age of the sand is where to start.  Typically sand can last well over the manufacturer’s recommendations of 3-5 years. I have used mine for well over 5 years maybe 7 or 8 seasons of normal use. Still, it is a sign that the sand filter might be the problem. You need to take steps.
  2.  A change in the Backwash Cycle. The backwash cycling time is normally no more than 2 or 3 minutes. The normal pump pressure will drop down 8 to 10 lbs. after the backwash and rinse. Too long a backwash cycle and you’ll start blowing excess sand out of the filter.
  3.  Pressure readings bump high and then low. This could be caused by Clumping and Channeling. This could be live algae or mineral deposits in the sand. A substance on top of the sand affects the filtering efficiency.


  1. Sand or Dirt is in the pool. This could be Damaged O-rings or Gaskets or maybe a broken or cracked lateral located on the manifold of your filter. You will need to inspect these laterals and replace them if necessary. The gasket or O-ring on the bottom of a multi-port valve might be damaged. If you have a push-pull piston-type backwash valve, the O-ring may need to be replaced. When an O-ring or gasket becomes worn, water will go right past the filter and back to the pool. The handle won’t seat itself right in the position you have it in.
  2. Using the Multi-port handle without shutting down the Pump is a No-No. If you are getting lazy and are moving the multi-port valve without turning the pump off, that could cause a bunch of mechanical problems. One is that the backwash water could be coming into your pool. The best time to inspect your sand and the inside of the pool filter along with the O-Rings and Multi-port valve is before you open your swimming pool in the Spring along with the pool pump and the filtration system that should be empty from your draining the water in the Fall when you closed the pool and the sand will be dry and easier to handle.


Once you decide that there is a problem with the Sand Filter and it’s not the Chemistry of the pool water. Go ahead:


How to Replace Pool Filter Sand


  • Power down your system
  •  Remove the Multi-Port Valve– loosen the collar- if you have a Top Mount Multi-port and need to cut PVC couplings and connections to and from the Multi-port, make sure to leave
                                    Lateral Stand Pipe

Lateral Assembly with Standpipe Inside-clear pipe to reconnect it when you’re done. Or Swap


  • Shine a flashlight inside the filter when you pull the Multi-Port Valve, You will find a layer of yucky hair, grease and God knows what else is there on top. Use a trowel a take off the top layer.
  • Move the Standpipe aside carefully not to break it, and inspect the top of the sand and walls of the inside of the vessel.


  • Replace what you take out. This should be good enough. When I have done this, the sand underneath is normally clean and good to go. I have gotten a few more years out of my sand by adding a bag of sand and an additive that will help clean the rest. The Sand Cleaner is sold in any pool store. If you decide to empty all the sand and replace it then:


  • Remove the rest of the pool sand with the trowel and a small plastic beach bucket or coffee can until you can get down to the Lateral Assemble-fold the ends of the lateral arms up towards you, like an umbrella, and remove it. Rinse it a couple of times. The arms have small slits that the pool water moves through. Sometimes they will clog up.



  • Rinse out the remaining sand through the drain in the filter and you are good to go.
  • Fill the tank with new sand. Use the fill line on the Inside-top of the swimming pool filter and always check the Plate on the outside that will tell you the exact amount and type of filtering sand to use. Never use anything but what is specified by the manufacturer.


Sand Filter Media Zeolite Sand and Glass Sand


The only type of sand that is used in swimming pool sand filters for your swimming pool is Silica Sand sized according to the specifications of your Sand Filter. There is no other type of sand. The most commonly used pool filter sand is #20 silica sand.

It comes from ground quartz, which creates sharp silica grains with jagged edges excellent for trapping particulates from passing water. Other types of media for filters may be acceptable but are more expensive. There are new recycled media that work but you need to check before using them.

If you’re looking for filter media with low environmental impact, glass sand is an effective alternative to swimming pool sand like silica. It’s made from 100% recycled glass and is smooth to the touch, but still captures particles as small as two microns—that’s one-millionth of a meter.

The glass grains are all different sizes, so it minimizes channeling, which occurs when pool water cuts a path straight through the sand and slips through the filter virtually unfiltered.

Glass sand also has a negative charge, so it excels at capturing iron and manganese particles. This is especially helpful if your pool is filled with a hard water source.

Zeolite Sand-Created from volcanic rock minerals called zeolites, this silica alternative boasts 100 times greater surface area than standard filter sand because of its sponge-like honeycomb shape. Zeolite chemically traps chloramines the chlorine byproducts that sting swimmers’ eyes through a process called molecular sieving.

That’s a fancy way of saying chloramines become trapped inside the zeolite sand particles indefinitely.
If you’re finding you need to shock your pool frequently, zeolite could help get chloramines under control without having to use as many pool chemical additives.

All this is fine information about the size and different types of sand and is good knowledge. But the Sand that is recommended by the people that make your equipment is really all you need to know.

If it’s Hayward and it’s a High Rate Sand filter-the size will be on the outside tag on the Filter’s tank. If you want to use a product that is recycled call Hayward don’t take advice from me or any other person on the web.

How Much Sand Does a Pool Filter Hold


If you decide to change all the sand out and have a pool service come by and take your filtering system apart and swap the sand, it could up to $500.00 plus the cost of sand you use. It’s well worth it to do it by yourself the project is not that hard. But it will take some time and you might need a helper. It might take you a day or so.

If you see signs of channeling or clumping, I would take the top a couple of inches off and add some new sand. A  50 lb. HTH pool filter sand, for use in most sand filters, with active ingredient crystalline silica, quartz 87-99% is what’s used.

HTH® Pool Filter Sand can tell you that it is Grade 20, 0.45 mm diameter Silica Sand.  works with most Sand Filters. Still, they recommend consulting the filter manufacturer. You can get specs for sand and pump rates right on the front of your filter or find them in the manual that came with the pump.

You will also need a Sand Filter Additive that is added to your skimmers and will enter your filter and the system will solidify deposits of oils, minerals, and grease that cause the channeling and clumping. This will free up your sand and it will start to perform a whole lot better. One bag of HTH quality pool sand with the right sized crystal according to the manufacturer’s spec and the additive is under $100 bucks.

This project should be done at startup before you open the pool and when the sand in the filter is dry. This makes a big difference when you are trying to handle the vessel and the weight is a  huge factor.

Sand filtering is affected by:

  • Usage
  • Oils such as suntan lotions and moisturizing creams are brought in from the tanning crowd who apply the dip to cool off then apply them again. On a hot day in August that could add up. The oil accumulates on the top of the sand where it starts to accumulate and clog the media.
  • Hard water that is running over time also accumulates in the system over the top layer of the sand. So when you pull the Multi-port valve, it will be the first 6 inches of the sand layer that takes the most beating. Once you do this you will be able to make the decision whether to take off the first layer or go ahead and swap out all of the filter sand.
  • A Worn O Ring on the Multi-handle or any Leaks or cracks in the Lateral Assembly can be easily replaced and ordered online by you as long as you get a visual inspection, you can get to it easily.


The time to inspect your sand filter is when you suspect that there are underlining mechanical problems with the filter. You can sense them if they are happening. Once you know how your filter sound and acts and what pressure ranges it works at then you can be in total control. I got to a point where I could spot trouble by listening to the system long before I had to take my wallet out.

You don’t have to change your filter sand every 3 years but if you call the pool store they will tell you that you do. It’s not their fault they are in business to make money. They make all their money in the mad rush when everyone is opening their pool.  So they will push sand at the beginning of the season.

Changing the swimming pool sand in your filter is a physical process. It’s not Biological or Chemical and It’s Not Complicated.

You can take and pour a bucket full of pool water through a bucket of sand and drain the water out a hole in the bottom of the sand bucket that will filter out the material that is the same size or bigger than the sand media. If the recommended size of the sand is 22 microns then the material filtered out will be similar to or bigger than that size.

If the pump is not pumping at the rate that is specified or engineered for the filtering system- that will affect its filtering efficiency. Backwashing efficiency will also eventually affect Filtering efficiency.

Your swimming pool can probably last 15 years if your Chemistry in the pool is right. You physically clean-skim-scrub your pool. And if you try and keep foreign contaminants from entering the pool water that would come from suntan lotion or any other grease or oils that block the sand.

That will affect overall filtering and the quality of your water. That’s why public pools demand you shower before using them.

Be the Master of your Swimming Pool.

The Chemical Treatment (Alkalinity-PH-Chlorine Residual) in your pool water depends on the Physical Treatment (The Sand Filter) efficiency in your Pool.

The Physical Treatment in Your Pool Is dependent on the Chemical Treatment’s efficiency in your Pool. When both are right you’ll be sipping a cold one on your float listening to the baseball game and not spending money at the Pool Supply Store on the 4th of July weekend.

My Best Tip:

The next time you’re in your swimming pool reach down, grab a handful of water and squeeze your fingers together. Hard water will fall and break apart if it’s thin with no consistency.



Why Am I Getting Sand In My Pool

For great information on balancing pool water and improving filtration stay right here at MyWaterEarth&Sky-basic high-rate sand filter is just that basic and the parts that operate it are replaceable and can easily crack or break after hours of usage. There are signals…………………..Continue reading


JimGalloway Author/Editor



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