Can I Use Pool Filter Sand in My Aquarium?

9 min read

Starting a new aquarium can be very exciting.

It can also be very expensive. One of the most expensive parts of a new aquarium is going to be your substrate (the stuff in the bottom of your tank). If you do your research on the cheapest sand out there it will eventually lead you to ask:

Can I use pool filter sand in my aquarium?

The main answer is YES! A lot of people use pool filter sand in their aquariums to save money. Especially in a large aquarium, you can buy pool filter sand in a 50 LB. bag for less than 10 dollars. If you buy made-for-aquarium sand, you are going to spend around a dollar per pound. You can use pool filter sand in your aquarium as long as you rinse it.

What is Pool Filter Sand?

Pool filter sand is mostly silica sand. It is fine sand – about .45 – .55 millimeters in size. Pool filter sand is extremely small because it is designed, as its title implies to be used in pool filters to help clean your swimming pool.

The finer or smaller the grain size is, the more dirt and debris your pool filter will grab. This is great for a pool filter, but it can cause problems for your aquarium if you are not careful. So, if it can cause problems for your aquarium, why would people even use it?

Why is Pool Filter Sand So Cheap?

So, here’s the kicker – you can buy a 50 lb. bag of pool filter sand for around 10 dollars. That’s around .20 cents per pound. When you are buying ‘made for aquarium‘ sand you are going to pay a dollar per pound or more. If you have a large tank you could end up saving up to a hundred dollars.

The savings from buying pool filter sand is the main reason that people use it in their aquarium. If you use strategies like this, especially for a large aquarium like 20 – 55 gallons or more, you can save hundreds of dollars.

Another cool thing about aquarium sand, which some people think is a drawback, is that you should wash pool filter sand before you put it in your tank. This is cool because you should wash it outside so in the summertime it gives you something to do outdoors and gives you a more hands-on experience with your aquarium.

Before you wash your sand though, let’s talk about which pool filter sand is the best for your aquarium.

Which Pool Filter Sand is Best for an Aquarium?

If your pool filter sand is cheap then it probably doesn’t have any additives, which is what you want. Stay away from treated pool filter sand if you are going to use it for your aquarium. Some of the treated sand even aids with chlorination. You don’t want chlorine or other chemicals in your aquarium.

Fine Grain Sand Can Ruin Your Filter!

You want to try to buy your pool filter sand as coarse as you can get it. This is where it can get confusing. You’re using it in an aquarium and not a swimming pool, so you want the grain size to be bigger. The reason is that the finer the sand is the harder it is to vacuum or keep clean.

Also, the finer the grain size is, the more likely it is to get caught in your aquarium filter. Most aquariums have a built-in pump, so if some sand gets into it, your impeller can seize and stop the whole filtration process.

Buy # 20 or Lower Sand!

When you buy pool filter sand for an aquarium, you want it to say # 20 mesh or lower. To understand this number just think of your window screen. 20 mesh means there are 20 squares per inch on your screen. 20 mesh means your sand grains will fit through a screen with 20 squares.

For example, if you got 15 mesh sand the grain would be bigger because your sand would fit through a screen with 15 squares per inch. If it were 25 mesh your sand grains wouldn’t pass through the screen unless there were 25 squares per inch in the screen. If there were only 4 squares per inch, the sand would be huge! Do you get my drift (no pun intended)?

With aquariums, you want your sand size as big as possible so it will be easier to vacuum and less likely to float up, if disturbed, and get caught in your filter. Now here are the 3 main brands that people buy for their aquariums:

HTH 67074 Filter Sand Care for Swimming Pools, 50 lbs.

HTH pool filter sand can be used in your aquarium

This is at least 20 mesh, you can usually find this brand at your local Hardware store or Amazon

FairmountSantrol AquaQuartz-50 Pool Filter 20-Grade Silica Sand 50 Pounds

IMG 8930 PetAquariums Can I Use Pool Filter Sand in My Aquarium?

This is a 20 gradation, you can usually find this brand at your local Hardware store or Amazon

Quikrete – 50 lb. Pool Filter Sand

Quikrete pool filter sand can be used in your aquarium

This is a 20/40 gradation that is usually at your local Home Depot store or Amazon

With pool filter sand you can usually go to any hardware store or Walmart. Just look for pool filter sand with no additives and at least 20 mesh or higher. The above brands are the most popular brands used for aquariums.

How to Wash Pool Filter Sand for Your Aquarium

Any time you wash any type of sand for your aquarium, it should be washed outside if possible. If it is wintertime, you live in an apartment, or any other reason to keep you indoors, you can wash it in your bathtub.

The reason you want to wash it outside is that you don’t want all the dirt and debris to go down your drain. However, if you must wash it inside, just do it in your bathtub and don’t stress about it.

Steps to Washing Sand Inside

  1. If you wash it inside just fill a five-gallon bucket about half full of your sand.
  2. Try to fit your bucket under your tub faucet, even if you have to tilt it.
  3. Run water into the bucket while working it with your hands.
  4. Let the water overflow and keep running. It will carry all of the dirt and debris out of your sand. The sand is heavy enough that it will stay in the bucket.
  5. Let the water overflow out of the bucket until the water that is coming out is completely clear.
  6. If you have the time you can keep working the sand in the bucket with your hands or a stick to clean it faster.
  7. If you don’t have the time, you can just let the water overflow and go do something else. Just go back in periodically and stir the sand up.
  8. Once you are able to stir the sand and the water is coming out clear, the sand is ready to put in your tank.

Washing Your Sand Outside

The process is the same if you are washing your pool filter sand outside. You can use a bucket and just let the water overflow. The dirt and debris that rinses out is not dangerous for grass or other plants which is why it is more practical to do it outside. Besides, your kiddos will want to help, and everybody can get outdoors.

If you use a sprayer attachment you can pretty much bury it towards the bottom of the bucket and let the water run. The sprayer will pretty much stir up the sand by itself.

However, if you have the time, it is always best to keep stirring or working the sand with your hands until the water comes out clear, it will go much faster.

Extra Tips for Washing Outside

Use a wheelbarrow to clean  pool filter sand in your aquarium

Wheelbarrow – Since you are outside, you have more room to work with. You can use a wheelbarrow to hold more sand. Just spray it or fill it with water. Work the sand with your hands. You can still let the water overflow or just tip the wheelbarrow to let the water flow out. The sand is heavy enough that it will stay in the wheelbarrow.

Paint Strainers – These strainers are shaped like a bag. You can get them at your local hardware store. Just fill them with sand instead of paint. You can either keep dipping the bag of sand into a bucket full of water, spray the bag with your hose sprayer, or a combination of both.

Vacuuming Pool Filter Sand

When you go to vacuum your pool filter sand be careful. With the normal vacuuming method, you will just suck a bunch of sand up your hose. The aquarium vacuums are made to gravel aquarium gravel, which is heavier than sand.

When you vacuum sand, you can’t just shove the vacuum down into the sand as you do with gravel. Just get close to the sand surface slowly without actually touching it. You will see gunk and detritus start to go into your vacuum.

Once this happens, slowly skim the surface of your sand with your vacuum. Keep your other hand on your vacuum hose so if you start to suck up your sand you can crimp your hose and let the sand fall back in.

Best Vacuums for Vacuuming Sand

TERAPUMP Genuine Aquarium Pond Fish Tank Cleaner Long Nozzle Water Changer Flow Controller BPA Free

terapump vaccuum is great for cleaning pool filter sand in your aquarium

Model: TRFTCLN has a large suction tube that allows for use in bigger Aquariums ( 10 Gallons or Greater ).

Discharge hose clip included (2019 Updated). Simply attach the discharge hose clip to your container this prevents the hose from falling off the container.

Two types of nozzles: the shorter nozzle is for drainage and the longer nozzle is for cleaning fish’s leftover food, droppings, and fine gravel. Takes the waste out while replacing the water and it will not hurt any aquarium life when in use.

Suction Cup: Securely keeps the suction tube in place allowing the pump to operate with one hand.

The filter will keep large gravel from entering the pump to prevent blockage while operating ( 1.5 gallons per minute ).

KASAN Gravel Cleaner Pump Aquarium Long Nozzle Cleaning Kit Tool, Aquarium Siphon for Cleaning Sand.

kasan gravel cleaner to clean pool filter sand in your aquarium

Multi-Function Cleaning Kit: The KASAN Gravel Clean Long Nozzle Cleaning Kit enables a multi-purpose when cleaning the fish tank. It can wash the sand, scrape the algae, absorb the remaining debris, and beautify the sandstone arrangement. It can make your aquarium cleaner and is also a vacuum cleaner in the aquarium.

Equipped with many accessories: pneumatic buttons, valves, algae scrapers, inlet tubes, outlet tubes, and air clips.

Reasonable design: The valve supplied with this product will not block the gravel and will not suck the fish. The algae scraper is a plastic material and you don’t have to worry about affecting your fish tank.

Wide range of applications: The kit is equipped with two 15.7-inch inlet tubes. The installation length can be selected according to the height of the fish tank. Therefore, it is suitable for aquariums of various sizes. See the installation video for the installation process.

Problems with Pool Filter Sand in Your Aquarium

The main problems I’ve found with pool filter sand are the vacuuming, which we discussed above, and detritus and gas getting trapped beneath the surface of the sand. Gas gets trapped because nitrates or nitrates sink down through the sand. Nitrites and nitrates are nitrogen and oxygen. When they sink down through the sand the nitrogen gets stripped of its oxygen and becomes a gas again.

The gas will usually rise up out of your tank into the atmosphere. However, pool filter sand is so fine that the gas can become trapped. All you have to do is vacuum the surface of your sand as described above. Next, make sure you run your fingers or stick or something through your sand. This will release any of the trapped gas. You can then vacuum the surface of your sand again.

Usually, you will have leftover sand since you are buying it in 50 lb. bags. If you end up vacuuming up too much sand you can always put another layer of sand in your aquarium. Just make sure you wash it.

Use a Pre Filter

This is basically a piece of foam that you stick on the end of your filter where the water intake is. It just keeps sand from entering your filter so, no worries!


I hope we have answered your question “Can I use pool sand in your aquarium and how to clean it.”

If money is not an issue, I recommend buying an easier ‘made for aquarium’ sand like ‘Caribsea Super Naturals Aquarium Sand’. Just keep in mind a 20-pound bag will cost 20 dollars for a 20-pound bag versus less than 10 dollars for a 50-pound bag of pool filter sand.

If money is an issue, just buy the pool filter sand and don’t stress over it. Clean it really well and move on so you can enjoy your aquarium. If you have any issues or concerns sign up with some online aquarium forums like they will answer your questions quickly.

Play sand is another cheap sand alternative, click here to view our article about using play sand

Remember, at the end of the day it is still sand, so relax and happy aquarium.

Written by:

Pet Aquariums

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