Substrate Vacuum Cleaners

What are Substrate Gravel Vacuums?

Substrate vacuum cleaners (also known as gravel vacs) are a cleaning device that is used to remove debris from an aquarium’s substrate. They are generally made of plastic and consist of a long cylindrical plastic tube which is often referred to as a gravel tube. The gravel tube has a wide opening on the end that’s submerged inside the aquarium. The other end is a long plastic hose (tubing) that will carry the waste water into a bucket. 

The main function of a substrate vacuum cleaner is to remove waste from the substrate of your aquarium. The waste matter includes fish poop, decaying organic matter, excess food and plant debris. All this waste settles down at the bottom of your tank and needs to be removed regularly to keep your aquarium clean. 

A gravel vacuum is extremely helpful and lets you quickly clean the substrate without needing to completely empty your fish tank. Cleaning the waste out of your substrate is a good way to do water change for your aquarium. Normally when you clean the substrate you will end up removing 25-30% of the water from your aquarium. It is a great time saver because you’ll be doing both at the same time. 

How do Gravel Vacuum Cleaners Work?

Using a substrate vacuum is easy. The open end of the tube of the substrate cleaner needs to be submerged inside your tank. The open end should be placed just above the substrate and the tubing on the other end of the gravel tube should be placed inside a bucket. Depending on the size of your aquarium you may want something even larger than a bucket especially if you intend to do a large water change. It’s extremely common to not realize how full your bucket is and get dirty aquarium water all over your floor.

There are a few different ways to get a siphon going with your vacuum. All methods require the aquarium/vacuum to be higher than the bucket it empties into. The easiest we have found is where you place the tube end into your bucket and your vacuum end into the aquarium. Lower the vacuum into the water with the open side at about a 45 degree angle. Fully submerge it and let it fill with water.

Once the gravel vac has filled with water you can raise it a little out of the water so that the water inside will start to drain through the tubing. Once you see the water heading through the tubing dip the vacuum end back under water. The water flowing through the tubing will create the suction you need to vacuum your aquarium.

You will want to pinch the tubing to control the water flow. The pinching will let you control how much water you suck up as well as keep your substrate from being sucked up by your vacuum. You can completely pinch the tube shut to the point where no water flows, and you’ll still maintain the suction you’ll need to vacuum when you want to start again. When you are ready to continue vacuuming you can stop pinching the tube.

For fine substrates like sand, most of what you will want to vacuum will have collected on the surface of the substrate. You can make passes up and down your aquarium just above the surface of the substrate and you will collect most of the waste. 

If you know you have waste in your substrate you can pick up some of the sand with the vacuum and pick up some of the sand. You’ll want to pinch the tube regularly so that you let the sand fall back down before sucking the dirty water further up. It might seem like this will be hard, but after a few times most people get the hang of it.

For other less loosely packed substrates like gravel you will want to push the vacuum into it. With this method you will pinch the tubing more than the other method. When you push the vacuum into the substrate you will not only suck up waste, but also some of the substrate.

What we recommend is that you push the vacuum down into the substrate with the tube pinched. You release the pinch for a second or two and you pull the vacuum out of the substrate and pinch the tube again. When you pinch it after it has been pulled out of the substrate it will allow all the heavier things like your substrate to fall back, while the dirty particles you want will be suspended in your vacuum. Then move to the spot right next to it and repeat until you’ve covered your entire aquarium substrate.

When vacuuming around plants there are a few things to consider. It’s best if you can avoid pressing the vacuum into the roots. If you do suck them up just pinch the tubing so that they can be put back into place. Another reason to not clean around the plants is that the waste you are cleaning is what they use for nutrients. If you can clean the rest of your aquarium well, it might not be a bad thing to skip the area right around your plants and let the waste act as plant food.

Types of Gravel Vacuum Cleaners

Substrate vacuums are available in three different types. The main difference between them is how they operate.

Siphon Vacuum Cleaners

Siphon vacuum cleaners need to be operated manually to siphon water from the tank. They use suction and gravity to pull the water from your fish tank. These are very inexpensive and the most commonly used gravel vacuum cleaners.

Siphon vacuums are available in a wide range of sizes and are the best substrate cleaners for new and even some experienced aquarium owners. They’re nice because you don’t need batteries or electricity to use them and they’re not difficult to operate. 

They do have some downsides as well. Because they need to be operated manually, it can take a lot of time and effort for the siphon vacuum to clean your aquarium. You can also drain out a lot of water from your tank while trying to remove the debris from the substrate. It’s not difficult to quickly remove more water than you planned to if you are not careful. There can also be spills while siphoning the water because you need to make sure the bucket you are filling doesn’t overflow or tip over.

User Experience: Beginner

Cost: $6 to $20

Electric/Battery Gravel Vacuum Cleaners

These are slightly different from the siphon vacuums and they’re either battery powered or plugged into an outlet. They use a motor to automatically pump the water from your aquarium. Electric gravel vacuums use a filter that sits on the top or is attached to the side of the gravel tube. When the water enters the tube it is run through a filter and flows back into the tank. This ensures the water level in your aquarium doesn’t drop. Some have an option where you can remove the filter and it will push the water into a drainage tube that will let you drain it into a bucket. 

Electric gravel vacuums help you make less of a mess while you clean your aquarium. They are very easy to operate and you don’t need to worry about spilling water. Some electric gravel vacuums also come with different hose options, allowing you to change them to clean different types of substrates. 

One major concern is that you need specific water levels to use electric vacuums. The water level restriction is because the upper part of the gravel tube has batteries or electronics that can’t get wet. Because of the electronics you are unable to submerge the entire unit. This is not a problem with siphon vacuums. Another problem is the batteries getting drained. We recommend buying a quality rechargeable battery. Being able to recharge the batteries will keep the batteries from running out while you use them.

The electrical vacuum cleaners are more expensive than siphon vacuums and are only available in a few sizes. They have lower suction levels which can take longer to clean the substrate. Even the best electric options we’ve seen lack the suction power of a siphon substrate vacuum. This can make water changes more difficult. You may need to buy a siphon vacuum to do water changes if the electric model you have doesn’t have a drain option.

User Experience: Medium

Cost: $25 to $60

Faucet-Powered Substrate Vacuum Cleaners

These are very similar to the siphon vacuum cleaners with the only difference in how it creates the siphon. Facet-Powered vacuum cleaners come with an adapter that is installed on your sink. 

There are three different holes on this vacuum. One will attach to your sink with an adapter. Another will have a tube that leads to your vacuum, and the last is where the water drains out into the sink. There will likely be a valve on the water drain portion. This valve will control if you suck water from the tank, or if you want to use the faucet to fill your aquarium.

Once the sink is running, the adapter will create a suction in the tube to siphon water from your tank. You can then use the gravel tube to remove debris or perform water changes just like you would do with a siphon vacuum cleaner. This type of vacuum is very popular because it eliminates the need to have buckets or the chance of spilling water. All of the water goes right down the drain without any worry about spilling anything. They also allow you to refill the aquarium after you’ve cleaned the substrate and done a water change. Just don’t forget to make sure the temperature is at the right amount, and add a dechlorinator if needed. 

The downside to these substrate vacuums is that it can lead to excess water waste because the tap water needs to be switched on to siphon the water from the fish tank. They are also the most expensive type of substrate vacuum cleaners.

User Experience: Medium to Expert

Prices: $40 to $100

Which type of Substrate Vacuum is Best for Me?

All the types of substrate vacuums will help you to remove debris and dissolved chemicals from your tank. It all comes down to your individual preference of how you want to clean the tank, and what you are comfortable spending.

One important thing that will help you decide which substrate vacuum to buy is the size of your tank. This is because substrate vacuum cleaners are available in different sizes. The difference is in the diameter of the opening and length of the gravel tube. The larger the size of your tank, the higher the diameter of your gravel tube. Most of the size options are only available in the siphon vacuums.

Being able to use the right size vacuum will ensure you can efficiently clean your fish tank without spending too much time. An opening that is too wide can drain your aquarium quickly and you may need to stop before you can clean the entire substrate. Something to consider the length of the tubing attached that the substrate vacuum comes with. This is really important because the right length of tubing can help prevent water spills during the water changes.

We recommend buying a gravel vacuum based on the size of your aquarium.

Aquarium Size Diameter of Gravel Tube

5 gallons 1 inch

5 to 20 gallons 1.5 inches

20 gallons and more 2 inches

Some people will buy different sizes of substrate vacuums. If you have a large tank you can use smaller substrate vacuums to remove debris around the areas that have living plants. The rest of the area can be cleaned using a larger substrate vacuum. This will minimize the risk of siphoning up the roots of the living plants in your tank. Another popular option is to not vacuum around your plants at all because the fish waste that has collected acts as a natural fertilizer. This doesn’t apply to a sand substrate because the fish waste tends to collect on the surface and is out of reach of the roots.