How to Clean Aquarium Gravel? Step-by-Step Guide

One of the most important decision to make when it comes to setting up your own fish aquarium is the choice of the substrate. One of the most commonly used substrates by most of the fish keepers is the “Gravel substrate”. Apart from giving your fish tank a natural and beautiful aesthetic, gravel substrate is also

important to fish’s health and growth. Benefits of gravel substrate will be discussed later in this article.

An important question that arises with the use of gravel is how to clean it? As a lot of fish waste, food leftover articles and plant debris can get trapped within the gravel. All these harmful substances can prove hazardous for your fish.

In this article we will be highlighting the benefits of gravel as a substrate, how to get a good as new gravel, easy and beneficial methods of cleaning the aquarium gravel.

Let us dig into this article and find a solution to your unhealthy gravel problem.

Why is Using the Gravel Substrate Important?

Although gravel is not your last or only option when it comes to aquarium substrate. Some people prefer a bare-base aquarium. Which means no substrate at all.

Although, this option is cost-friendly and does not cause you the hassle of cleaning. But a bare-base or non-substrate aquarium doesn’t fulfill the natural criteria of fish habitat. Furthermore, it requires more cleaning, and it also lacks beneficial biological filter and useful Bacterias.

Moreover, “Sand-based Aquarium” is another option for fish keepers. There are both pros and cons of using sand as substrate such as it is not expensive, easy to find and use.

But on the other hand, it does not contain any essential nutrient, has less oxygen content and, complete absence of useful Bacterias for fish. Lack of vital biological filter means more cleaning will be required. It is also harmful for natural plants in the aquarium as they can die due to lack of oxygen.

Benefits of Gravel Substrate:

Now getting back to the main topic that what benefits can we get from using gravel as a substrate? Apart from bringing natural aesthetics, it is also a storehouse of beneficial Bacterias. Although it can entrap harmful substances like fish debris, waste, and products from dead plants, it is also useful for fish in some ways.

Waste in the fish tank is a major source of ammonia buildup, thus we need nitrifying Bacterias to eliminate these elevated levels. Gravel substrate is the main production and growth site of such bacteria. Thus, gravel substrate is an easy and natural source of eliminating unnecessary ammonia.

Moreover, it provides important sites for fish to interact. Gravel substrate is the closest thing to natural fish habitat. Thus, it is a stress-reliever for fish. Gravel also helps fish in lying and protecting their eggs.

Another important use of gravel is that it is also beneficial for plants in aquarium as it provides adequate support and oxygen. Above all it is easy to clean, which is our main concern of the day.

Different Types of Gravel Used:

There are different types of gravel available on the market that you can choose according to your taste and needs.

  • White aquarium gravel
  • Pink aquarium gravel
  • Pea gravel
  • Crushed coral gravel
  • Black and blue aquarium gravel

All you need is enough gravel to cover aquarium base up to 3 inches. Clean the gravel 2-3 times before adding it in the tank.

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What are the side effects of dirty and old aquarium gravel?

When it comes to dirty and unkept aquarium gravel, it can lead to dangerously high levels of ammonia, nitrates and other harmful substances. These substances can lead to disturbance in the pH of water, such changes can affect the fish’s health in the worst way possible.

Furthermore, with decaying matters like fish waste and food particles stranded within the gravel, there is excessive growth of algae. This alga can use up the available oxygen leading to the death of fish and plants as well.

Above all that, gravel is not only responsible for the growth of

useful Bacterias but also many harmful bacteria and microbes can thrive in it. Such toxic agents can cause disturbance in essential water parameters like pH, water hardness, and oxygen levels.

If aquarium gravel is not cleaned properly, it will make the water dirty and unhealthy in no time and will require frequent water changes. Moreover, it will be difficult to maintain suitable water conditions and will cause a huge nuisance for fish keepers.

When and How Often You Need to Clean Aquarium Gravel?

Any change in water color, water parameters or visible debris in aquarium or if your fish is moving slowly, then all of it is an alarm to rising levels of waste in aquarium. If you notice any of such changes, it’s your time to deeply clean aquarium gravel.

Apart from regular partial water changes, an aquarium with gravel substrate requires extra treatment and effort. The cleaning requirement, method and timing depends upon the following factors.

Aquarium size

In a large sized aquarium with less fish there is less waste accumulated per square foot and thus, less waste disposal is required. So, a huge aquarium requires less cleaning.

Types of fish present

Some fishes are huge and produce more waste. For example, Oscar fish eats more and ultimately adds a huge amount of waste to the tank, so it requires a deep cleaning more often than other fish.

On the hand, smaller fish produce less waste. There are some fishes like cleaner fish that automatically cleans the tank as a part their job. Such fishes require less cleaning, for them a monthly thorough cleaning is more than enough.

The quantity of fish in an aquarium:

The amount of waste is directly related to the quantity of the fish present. More the fish, more the food used and more will be the

waste. Moreover, overfeeding the fish is also a contributing factor as it leads to more waste, more food leftovers and more decaying

matter for algae growth. Thus, you should avoid overcrowding and overfeeding.

Presence of live plants:

Live plants are another source of waste reduction thus the aquarium with live plants need less cleaning. Weekly a vacuum cleaning is more than needed, provided you keep a check on the plant debris.

Quality of Gravel used:

The type and quality of gravel is also an important factor. As cheap and low-quality gravel can disintegrate with time adding a huge amount of limestone in the aquarium water.

Thus, a high-quality gravel should be preferred. Moreover, small sized gravel can trap more waste in its small air pockets and such pockets can lead to gravel hardening.

Large sized gravel entraps less waste and its easy to clean as well. Even with a single round of vacuum cleaning can remove large percentage of waste in this type of gravel.

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Based on all the above-mentioned factors it is recommended by aquarist to clean aquarium gravel every two weeks thoroughly with 25% water change. Moreover, a weekly vacuum cleaning is also recommended.

Methods to Clean Aquarium Gravel, Step-by- Step Guide:

The scheme of cleaning depends upon the resources at hand and the condition of your aquarium. There are generally two main methods of cleaning the aquarium gravel. We will be discussing both the methods in detail with step-by-step guide.

Cleaning the Aquarium Gravel with Vacuum System

The vacuum filtration system works on the principle of a sucking vacuum and gravity. All you need is a syphon or a long tube, a vacuum kit and a water bucket.

Cleaning the gravel with vacuum requires following steps.

1.Removing the Aquarium Components:

First, you need to prepare the area for cleaning which includes removing all the machinery such as water heater, filter, and water pump. Moreover, remove the decorations, rocks, and plants. Leave the fish and live plants inside.

Usually, the vacuum cleaning method does not take more than 20-

30 minutes and its likely that your fish can survive this brief time.

2.Setting up the Apparatus:

Firstly, place the bucket at the lower level of aquarium. Take the syphon or the long plastic tube and attach it with the vacuum machine. Sometimes the syphon is already a part of the vacuum kit and thus it makes your job quite easy.

Next plug the open end of the syphon with your thumb, submerge the syphon into the water a few centimeters above the gravel.

3.Begin the Vacuuming:

Once the syphon is completely submerged in the water and its close to the gravel, withdraw your thumb and let the water run into the bucket. Check the flow of water and once its fluent move the syphon into the deeper parts of gravel.

Move the syphon’s head up and down as well as in to-and-fro directions, it will allow more waste removal. There is usually more waste accumulation around the plants and decorations thus these areas require more cleaning.

It should take maximum 30 minutes to thoroughly clean the aquarium gravel. Move the gravel around to ensure complete eradication of waste material. Make sure to break all the hardened gravel pockets.

Once 20-25% of water is removed along with waste its your time to stop.

4. Removing the syphon:

As soon as the water levels drop to the 3/4th  of the original level, turn the mouth of the tube upward and move it out of the tank. Make sure that whole water is drained out of the tube into the bucket.

Once the syphon tube is out of the tank, throw out the water and clean the vacuum machine by passing a round of clean water through it.

5.Checking the water parameters:

Now fill the tank completely with freshwater, it is advised to avoid using the tap water as it is loaded with minerals. Its vital to check all the water parameters before finishing the process.

Check the pH, concentration of ammonia, nitrate, nitrite, phosphate, and water hardness.

Make sure all the parameters are stable and appropriate. Some aquarists tend to add de-chlorinating agents in case of tap water after cleaning, for this purpose you must remove fish and plants

before cleaning process. Removing the fish is necessary as these agents are harmful for fish.

6. Putting all the Components Back in:

Now its time for you to set all the components back in. Set the water heater, filtration system, water pump and decorations into their original location.

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This cleaning process should be repeated every two weeks to ensure the safety of your fish.

Cleaning the Aquarium Gravel without Vacuum:

Well to clean the aquarium gravel without the vacuum kit is quite difficult and requires a lot of effort. For effective cleaning you need to follow all the essential steps carefully and precisely.

All you need is a separate tank setup, a fish net, a syphon, scrubs, and some cleaning agents.

1.Setup a Holding Tank:

The very first step in cleaning the gravel is to setup a separate aquarium. Remove all the essential components including the water heater, water pump, filtration system, decorations, plants,

and fish as well. It is important to remove the fish as we are aiming to remove all the water and gravel.

Transfer 50% of water into the separate holding tank to provide the same conditions to fish as before. As drastic water changes can affect the health of fish.

2.Cleaning the Gravel:

Once the tank is empty you should remove the gravel as well. Move the gravel into a separate bucket and wash it thoroughly with water. You should wash the gravel 2-3 times deeply to ensure complete elimination of waste products and harmful bacteria. Air-dry the gravel to eliminate any toxic agent left behind.

It is crucial to separate a small amount of gravel aside, as this gravel is the main reservoir of beneficial bacteria. If whole gravel is devoid of essential bacteria, then it will lead to pilling up of ammonia in aquarium. Once bacteria are removed completely you will need to add bacterial culture on your own. Thus, it is vital to save up some gravel with active bacterial cultures.

3.Cleaning the Tank:

Next step is to carefully clean the aquarium with disinfectants. Avoid any strong and harmful chemicals as they have long- lasting harmful effects. If any strong chemical is applied, make sure to clean the aquarium surfaces multiple times to remove hazardous chemicals.

Once the aquarium is clean its best to air dry the aquarium. This step is essential as it helps in killing any harmful bacteria or pathogen and ensure the safety of fish.

4.Re-establishing the Aquarium:

Once all the components are clean it’s time to setup the aquarium once again. Now place the aquarium in the right place, spread the dry gravel on the bottom up to 3 inches on the side. Do not forget to mix the clean gravel with the one having bacterial culture left aside. This step is crucial as it will ensure the regrowth of essential bacteria and further cleaning the aquarium without any effort.

Once the gravel is settled, add fresh water, check water parameters, and ensure the maintenance of accurate water conditions before adding the fish. Now set in the decorations and essential equipment, then carefully add the fish to the aquarium.


Gravel is the most popular and most recommended substrate for aquariums, and it comes with some pros and cons. Although it is beneficial for fish and plants simultaneously, it isn’t easy to clean. The vacuum kit has made it quite simple and quick. Cleaning it manually is time-taking but not impossible, and we hope this article will help you clean your aquarium gravel in the best way possible.

2 thoughts on “How to Clean Aquarium Gravel? Step-by-Step Guide”

  1. Steps to Clean Old Aquarium Gravel: Step one is the standard cleaning solution: about 10% bleach and 90% hot or warm water, or you can use a lower concentration of bleach to be safe for fish after that. The second step is to put the fish gravel in the pot plus the bleach solution, pour the water to cover the gravel. Soak the gravel for no more than a quarter of an hour, during which time you can stir to irritate the cleaning solution. The fourth step is to rinse the aquarium gravel and then dry it. Finally, return it to the aquarium.

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