How to Prepare Gravel and Substrate for a New Aquarium

Wall mounted aquarium with tropical fish
Leonid Eremeychuk / Getty Images

Did you know that new gravel must be rinsed before putting it into the aquarium? Don't worry, it only takes a few simple steps. Here's what you need to know.

  • Difficulty: Easy
  • Time required: 20-30 minutes

What You Need

  • 6" or larger sieve
  • 5-gallon bucket


  1. Purchase enough gravel to cover the aquarium bottom approximately 2-3 inches deep.
  2. If you don't already have one, purchase a 5-gallon bucket and label it for aquarium use only. Aquarium buckets should never have soap in them.
  3. Place a large clean sieve, at least 6 inches across, over the bucket. Fill the sieve half full of gravel.
  4. Pour water over the gravel in the sieve, while gently shaking it. Rinsing the gravel over the bucket rather than over a drain allows gravel that slips through the sieve to be caught instead of going down the drain. Continue pouring water over the gravel until the water runs clear. Several washings are usually required.
  5. Once the water runs clear, the gravel is ready to be used. It may be placed directly into the tank or in a clean bucket or container.
  6. Repeat steps three through five until you have washed enough gravel to fill the aquarium 2-3 inches deep.


  • A rule of thumb for the amount of gravel to use is one to two pounds of gravel per each gallon capacity in the tank.
  • Old buckets may be used if they are thoroughly cleaned with bleach, rinsed well, and allowed to air dry.

An Alternative Cleaning Method

To properly clean new aquarium gravel, it must be done correctly!

Cleaning new aquarium gravel properly is an important first step in keeping water quality high; gravel dust and residue can harm or even kill fish. Even though new aquarium gravel may be marketed as “pre-rinsed” or “pre-cleaned” by manufacturers, bags of new aquarium gravel often contain dust, debris, grit or poisonous residue from the factory where it was packaged. These small particles should not make their way into a freshwater aquarium environment.

Fish Keepers often think these small particles causing temporarily cloudy water can be removed by an aquarium filter. This is partially true, however, much of the "dust" settles to the bottom of the tank, only to be stirred up whenever the gravel is disturbed. Improperly cleaned gravel is one of the major hidden causes of slightly cloudy water in newer aquariums.

The dye used in cheap gravel available at a low cost can discolor tank water as well as introduce poisons to your fish community. Having colored tank gravel could be your choice, but unless it is completely cleaned, it can be a long term danger to many fish.

The first step in cleaning aquarium gravel, the easiest way, is to pour one bag at a time into a bucket outside of the home or office. It is important to do this cleaning outside, the gravel dust will not harm lawns or plants, but it could permanently clog the trap in sink drains, this is a clog that will need a plumber to fix, do not clean gravel into sink drains!

With a high-pressure hose (normal outdoor water pressure, but with a spray head to increase the pressure at which the water shoots out of the hose) spray an intense stream of water into the gravel at the bottom of the bucket. The water will become cloudy with residue literally washed out of the gravel. Pour out the water covering the gravel in the bucket, again do not pour the water into a drain but on the ground. Repeat over and over until the water above the gravel in the bucket is clear after spraying the gravel. At this point, the gravel is clean enough to put directly into the tank. Empty the next bag of new gravel into the bucket and repeat.

Even after this process, you may have some clouding of the water, this is normal and the dust will settle. Using new gravel is another reason not to put fish in a new aquarium until it has been filled with water and filter allowed to circulate the water for at least a week.

To avoid any clouding of the water, a second step may be necessary. After fully cleaning out the dust and debris using the bucket method, get a large strainer and wash small amounts with the hose to get the last of the dust out of it, and then pour into the new aquarium.