A gravel vacuum is a long piece of rigid, wide tubing aquarists use to clean the gravel in fish tanks. The thin tube attaches to a cap that attaches to a longer, thinner, more flexible tube. The inside of the cap usually has a small opening. The opening slows down the flow of the water before it enters the flexible tubing.
The tubing uses gravity to create a suction. The suction pulls water and waste from the tank for an easy clean.
The device gets the name “gravel vacuum” for its purpose. While it pulls water out of the aquarium, its main job is to suck waste from between the gravel where it’s hard to reach.
The gravel is where much food and fish waste ends up if the filter misses it.
A gravel vacuum is the easiest way to remove waste stuck in the gravel.
Routinely gravel vacuuming an aquarium is essential for keeping it in pristine shape. The organic waste eventually breaks down into ammonia and nitrites without removal. These are toxic to fish and can cause illness and death.
Vacuuming an aquarium doesn’t require a lot of equipment. Use an old bucket, the vacuum, and sponges for cleaning the decorations (optional).
Before vacuuming, many aquarists clean the sides of the tank and decorations.
Aquarists must start the water flowing through the tubing to vacuum the gravel. There are three methods for starting a siphon:
- Using a faucet attachment
- Using a pump attachment
- Using a manual gravel vacuum
It’s unnecessary to remove fish from an aquarium before cleaning. Catching fish and moving them to a temporary tank is more stressful for them than leaving them.
Step 1: Clean The Sides Of The Tank & Any Decorations
Remove all decorations from the tank and give them a good clean.
Decorations can get quite dirty. Putting dirty objects back into a freshly clean tank doesn’t make sense.
Leave the decorations out of the tank until vacuuming is complete. They get in the way of the vacuum, making cleaning harder.
A lot of waste also gets stuck under the decorations, which needs cleaning.
Use an algae scrubber to clean the sides of the tank as necessary. The gravel vacuum sucks up any pieces of algae floating around after the process.
Step 2: Siphoning
The most challenging part of gravel vacuuming is getting the suction to start. It’s most difficult with manual vacuums.
Faucet and pump vacuums are easier to work with, though they are more expensive.
How To Start A Faucet Vacuum
Faucet vacuums are the easiest to work with, though the fish tank must be somewhat close to a sink. The flexible tubing is usually far longer than on manual or pump vacuums. The length allows the aquarist to run the tubing to the sink.
These vacuums usually come with a faucet adapter and attachment. The attachment allows aquarists to pull dirty water from their fish tank. It also allows them to pump fresh water back into the tank.
Follow these steps to use the adapter and attachment:
- Remove the aerator from the sink faucet.
- Screw the included adapter into the faucet. These don’t fit every sink — it may be necessary to buy the correct adapter at a local hardware store.
- Screw the vacuum attachment to the adaptor. The open end of the attachment should face downward toward the drain. The other end should come already attached to the flexible tubing.
- Most attachments have a valve to change settings. The valve may be different depending on the brand.
- Read the instructions to know which way to position the valve.
- One way creates suction and pulls the dirty water from the tank.
- The other way pushes fresh water from the sink, through the tubing, and into the aquarium.
- Turn on the faucet to create suction.
- Don’t turn the faucet on all the way — the pressure may be too much and cause water to spray out of the tank.
- Return to the tank and use the gravel vacuum to clean the gravel.
- Turning the faucet off doesn’t stop suctioning as long as the gravel vacuum is still submerged. Turning the faucet off only slows down the removal of dirty water.
- To stop the suction, the gravel vacuum must come entirely out of the water.
- To add fresh water back into the aquarium, ensure the gravel vacuum is inside the tank first. Switch the valve, turn on the faucet, and the water flows through the tubing and into the tank.
Ensure that the water going from the sink into the tank is the same temperature as the water already in the tank.
Dechlorinating the tank can be tricky when using a faucet siphon. Add a capful of dechlorinator every 30 seconds when filling up the tank. Doing so ensures that all the fresh water coming into the tank is properly dechlorinated.
Be sure to add the dechlorinator into the tank where the water flows out of the gravel vacuum.
How To Start A Pump Vacuum
Pump vacuums are like manual vacuums, though they are far easier to use. A pump sits in line with the flexible tubing.
The flexible tubing is usually far shorter than those included with faucet-style vacuums. Most aquarists run their tubing into a bucket they can dump once it fills with water.
Follow these steps to use a pump gravel vacuum:
- Completely submerge the hard, wide tube and cap in the water.
- Place the longer, flexible tube in a bucket sitting below the tank.
- Pump the bladder until water begins to come up into the tube.
- The water starts flowing freely once all the air is gone from the tube.
- Remove the gravel vacuum from the water to stop the siphon.
- Dump the bucket of water.
How To Start A Manual Vacuum
Manual vacuums are trickier than faucet or pump vacuums at first. After a few tries, they are no longer difficult to use and are cheaper than the other two vacuums.
Manual vacuums are very simple and have no attachments. They only include the rigid tube, the cap, and the long, flexible tubing.
Many seasoned aquarists start the suction of their manual vacuum with their mouths. Sucking on the end of the flexible tubing creates a siphon. It’s an easy way to pull water through the device.
While this method is simple, we don’t recommend it.
Aquarists rarely clean their siphons. They are dirty and may harbor bacteria or viruses.
It’s rare for aquarists to become ill due to their fish tank. Placing your mouth on aquarium equipment increases the odds.
It’s also gross getting the tank water in the mouth, especially when working with saltwater tanks.
Most aquarists remove their mouths before the water reaches the end of the tubing. It’s not always possible to be fast enough.
The good news is that aquarists don’t need to use their mouths to use a manual siphon.
To use a manual gravel vacuum, follow these steps:
- With one hand, hold the flexible tubing over the bucket. Hold the tubing so you can place your thumb over the tube’s opening when necessary. For now, keep your thumb off the end.
- Hold the hard tube with the other hand and place it underwater. Keep it parallel with the gravel bed.
- Slowly tilt the hard tube upwards — raising the tube out of the water may be necessary.
- Moving the tubing upwards allows water to begin flowing down the tube.
- The water should begin flowing through the tube. Place your thumb over the opening of the flexible tubing.
- Place the hard tube back underwater and keep it pointing slightly upwards.
- Holding the tube upwards allows gravity to push water through the tube. It also helps remove air bubbles.
- Remove your thumb from the flexible tubing once all the air is out of the rigid tubing.
- Removing your thumb begins the siphoning.
- Remove the gravel vacuum from the water to stop the siphoning.
- Dump the bucket of water.
Repeating steps five through seven may be necessary if the siphon doesn’t begin on the first try. There may still be air in the tubing that needs to go away for the siphon to work.
Step 3: Begin Vacuuming The Gravel
Once the siphon starts, vacuuming the gravel is quite simple.
Press the hard tube into the gravel until it reaches the bottom of the tank. Notice that the gravel swirls inside the tube, though it won’t get sucked through the tubing.
Depending on how dirty the tank is, a small plume of dirt should waft up from the gravel. The dirt gets suctioned through the tubing and exits into the bucket.
Lift the hard tube so the gravel falls back into place and move on to the next spot.
Try crimping the flexible tubing to temporarily stop the suction if the gravel won’t fall out of the hard tube.
Try only to clean a small amount of gravel at a time. The more gravel in the tube, the less effective the vacuum is at cleaning it.
Hobbyists should repeat this process until they’ve removed about 30% of the water.
Ideally, hobbyists successfully clean all the gravel in this timeframe. Sometimes, it’s impossible to completely clean the gravel before 30% of the water is gone.
To get the best clean, some aquarists prefer cleaning 1/3 of the gravel at a time. They gravel vacuum their tank once a week, focusing on a different section of the tank each week.
Clean the gravel as quickly as possible, as the cleaning process is stressful for fish. Move quickly while avoiding jostling things about or harming the fish. Moving too fast isn’t any good if it injures the fish.
Does Vacuuming Remove Good Bacteria?
No, gravel vacuuming does not remove good bacteria from the tank.
Such fear is valid since beneficial bacteria live within the substrate. Fortunately, sucking up the bacteria is nothing to worry about.
Good bacteria are microscopic and live deep within the crevices of the gravel. They are firmly tucked into the substrate. Occasional cleaning won’t disturb most of the bacteria.
Fish, plant, and food waste is much larger and easier to suction out.
Beneficial bacteria also live inside the filter and other places throughout the aquarium. Even if some bacteria get sucked out of the gravel, the tank won’t crash.
It’s best to avoid cleaning the gravel and filter simultaneously to prevent a crash.
Gravel Vacuuming A Planted Tank
Whether vacuuming a planted tank is possible depends on the plant type and density.
Some plants have thick root systems that won’t allow easy gravel vacuuming. Others are fragile and don’t like being disturbed. Heavily planted tanks are also difficult to gravel vacuum.
Gravel usually isn’t the best substrate for planted tanks, anyway.
How To Siphon Sand Or Fine Gravel
It is possible to siphon sand and fine gravel. We’ll need to slightly modify the above method to siphon sand or fine gravel.
Don’t place the vacuum directly into the sand or fine gravel. These substrates are too light and get sucked out with the dirty water.
Instead, allow the vacuum to hover about an inch over the sand or fine gravel. Sweep the vacuum back and forth to create a current. Doing so stirs up the substrate so the vacuum can suck up the waste.
Precautions
Take care when gravel vacuuming as it can cause injury to fish and invertebrates. Injury is rare; most organisms prefer to stay far away from the scary tubing, though it’s not unheard of.
Most fish are too big to be sucked from the hard tube, through the flexible tubing, and into the bucket. Even so, gently net them back into the aquarium if this happens.
To rescue big fish stuck inside the hard tube, break the vacuum’s suction. Gently help the animal out of the tube and watch them for injury or trauma. Consider adding API Stress Coat to the water to promote healing and reduce stress.
Don’t Forget About The Bucket!
Don’t forget about the bucket, or you might find the floor covered in water. It’s easy to get lost in cleaning and forget that the bucket is filling up with water.
Always keep an eye on the bucket and stop vacuuming before it gets to the top. Dump out the water and continue cleaning if necessary.
Aquarists should be aware of how much they can carry without hurting themselves. A 5-gallon bucket of water is much heavier than it seems — about 43-46 lbs (19.5-20.9 kg) when completely full.
Turn Off All Aquarium Equipment & Watch For Outlets
Always unplug the heater and filter before vacuuming an aquarium.
Most heaters malfunction if turned on and exposed to the air for too long.
Likewise, filters should not run when the water is below a certain point. That point differs for each filter — they usually have a minimum fill line. Filters are likely to malfunction and break if the water line gets too low.
Be careful when working around electrical outlets and ensure no splashing occurs.
How Often To Gravel Vacuum
It’s best to gravel vacuum fish tanks once every week or every other week. Routine cleaning is essential for a safe and healthy environment.
Dirtier fish, like goldfish, need cleaning about once a week. Less messy fish, like tetras, are usually okay to go two weeks between cleanings.
