How Much Sand for 20 Gallon Tank? How To Buy Good Sand

A not-so-secret tip for successful fish raising is to keep the tank condition as similar to your pet’s natural home as possible. 

Factors to consider are the water temperature, PH level, heat, caves, plants, and of course, the sand! Putting sand into the aquarium will bring a sense of familiarity to your fish, helping it thrive faster and better!

However, the sand quantity is another matter to discuss here; neither too little nor too much are good. Since 20-gallon tanks are the most common, the question of how much sand for 20 gallon tank is enough remains popular among the fishkeeper community. 

Our insightful article will deliver your long-awaited answer. Click here to learn more. 

How Much Sand for 20 Gallon Tank Is Enough?

tank with sand

For most standard fish tanks, you should allow a sand layer of at least two inches thick to sit at the base. Here’s a quick formula to figure out how much you need for a tank of 20-gallon capacity.

Step 1. Multiply the width and the length of your tank. Not all 20-gallon tanks have the same widths and sizes, so measure them carefully.

Step 2. Divide that number by 10. It will tell you how many sand pounds you should prepare for a 2-inch depth!

Let’s look at an example. Suppose the fish tank is 50” long and 15” wide. First, multiply 50 and 15 to receive 750. Next, divide it by 10, and you get 75lbs. That means you must purchase about 75 pounds of sand to achieve a depth of 2 inches for your aquarium’s bottom! 

Remember that certain sand types are much lighter than average. Take caution when choosing exotic options.

Other Tank Capacity Options 

Though 20-gallon tanks are popular, it doesn’t mean tanks of other capacities are not widely used. If yours is not of 20-gallon size, consider the following alternatives:

10 Gallons

In general, 10-gallon tanks require about 19.5lbs for a goal of 2-inch substrate. Use the formula introduced above to measure your tank and evaluate the needed amount. 

Keep in mind that smaller tanks are much more subjected to sudden and quick changes in their environmental conditions than bigger tanks. 

Why is that? It’s because their water volume is so small that it barely takes time for any content within the water to become diffused. It’s a factor you should consider when choosing sand!

Extra note: Suitable fish for 10-gallon tanks are zebra danio, neon tetras, cloud minnow, guppies, and betta.

30 Gallons

Roughly estimated, it often takes 64 lbs of sand to achieve a 2-inch depth within 30-gallon tanks. The precise shape of your tank also plays a part, changing the above estimation a few degrees. 

From experts’ perspective, 30-gallon tanks are among the most manageable ones; 20% of its water will change periodically, allowing you to stock the tank with numerous stunning fish types. Some examples are rainbow fish, guppies, cory cats, molly fish, angelfish, killifish, and goldfish.

40 Gallons

Tanks of 40 gallons are often similar in shape, with particular emphasis on height. As a result, the needed sand amount for 40-gallon tanks is usually much less than their 30-gallon counterparts. You only need 60 lbs to build 2-inch deep layers of sand in most cases!

Fish that can survive in 30-gallon containers will likely develop beautifully in 40-gallon ones, too. Certain fish prefer larger environments, such as cardinal fish, three-spot gouramis, and convict cichlids.

Stocking the tank with zebrafish, cory cats, betta, goldfish, mollies, and more is also welcome! Not only fish, but the bigger leagues of 40-gallon tanks give you more choices regarding plants, substrates, and aesthetic settings as well. 

Other Things to Consider When Choosing Sand for Your Tank

Water Type

Live sand will be the best for saltwater tanks, helping you form a good ecosystem for the fish. All the bacteria residing within this sand play an essential role in the filtration system, which fosters the fish’s natural and fast growth! And remember, it’s important to take care of that system as frequently as with your fish. 

What about freshwater containers? In that case, you are quite lucky since the available options are much more abundant. Living sand is not necessary, so feel free to choose the one you like. Even play sand is acceptable!

Fish Type

Fish Type

Some fishes prefer consuming bacteria off the substrate’s surface, while others like rubbing their bodies against it. Meanwhile, rarer cases witness the fish/tank dwellers bury their entire bodies into the substrate!

Assess which category above your fish falls into, then research carefully to find out which sand can support those habits best. Fine grand sands are usually the most appropriate, but not every fish is the same. You should check, just in case!


The sand color does not considerably impact how the fish grows (which fish care about that in the first place?), but it can decide how your aquarium’s aesthetics turn out. 

It’s all up to your preferences and decisions; also, ask yourself which accessories you like to adorn your tank with, as they might help you reach a decision quicker! 

Cleaning Process

For those wanting to use sand as their substrate, it’s important to assess how it will be kept clean. Some sand-sifting sea creatures can take charge of part of your burden; but cleaning the sand frequently is still a must, ensuring no anaerobic bacteria has room to flourish.

One common way to clean the tank’s sand is via a siphon/gravel vacuum or small shovels. Sometimes, using your hands to agitate is also recommended!



Having plants in the tank helps filter and oxygenate the tank’s water and feed the animals. But just like your pet fish, they also require sufficient living conditions to develop, including sand. 

Do you want the plants to grow long roots? Then choosing sands with fertilizer and lower pH levels is a good idea, encouraging them to extend faster. 

And do not forget to check whether those conditions suit the fish. Once every criterion is fulfilled, it’s time to make your purchase.


How much sand for 20 gallon tank is enough? What factors should I consider when buying sand? Our article has covered all these inquiries. Note them down to make sure your fish enjoy the best living environment!

For more guidance, feel free to reach out.