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How Much Sand Do I Need For My Aquarium? Facts & FAQs

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By Lindsey Stanton

discuss fish in aquarium

If you have a saltwater, marine, reef, or brackish water aquarium, you probably need to have sand as the substrate. Gravel is a good choice of substrate, but that is really only the case for freshwater tanks. Gravel does not do a very good job of creating a good marine or reef habitat, but sand definitely does. To be precise, we suggest using a sand calculator.

Sand is what these habitats have in the wild, and so these habitats should have sand as the substrate in your home aquarium. However, you might be wondering, how much sand do I need for my aquarium? Well, let’s talk about using sand as substrate and how much of it you are going to need.

seashell dividers

Using Sand As Substrate – Marine Environments

The reason why sand is the best choice of all is that it becomes home to various creatures and microorganisms that help to keep the tank alive. This is especially true when it comes to living bacteria which help reduce ammonia and nitrite levels in the tank, as well as some other unwanted substances.

The point here is that sand is the best way to go for these kinds of aquariums due to its ability to house bacteria and microorganism populations which end up being very beneficial for the overall health of the aquarium. You can use inert sand, which is just sand, or you can use live sand (we have covered our top 5 here). Live sand already comes with bacteria and microorganisms, so it provides you with a head start on the biological filtration aspect of things.

When it comes to how much sand you are going to need to form the substrate base in your aquarium, there are a couple of different factors you will need to consider. Do you want a tank with mostly plants or do you want more fish?

What kind of plants do you want to have? (we have covered our 5 recommended plants for sand here) What kind of fish are you looking to have? What kinds of decorations, filters, and other things are going to be present in the aquarium? At any rate, let’s move on and talk about these factors in relation to how deep you need the bed of sand in your aquarium to be.

aquarium with coral, clay pot, cichlids, plants
Image Credit: Frantisek Czanner, Shutterstock

The Depth of the Sand

There are varying levels of depth when it comes to sand in an aquarium. Generally speaking, this can be classified into two different depths, those being shallow, which is anywhere from 1 to 2 inches of sand, and deep, which can be anywhere from 4 to 6 inches of sand.

One thing to keep in mind here is that all sand beds will need to be cleaned and maintained, usually with a siphon or vacuum of some sort. Of course, seeing as there is less volume to deal with, shallow beds are easier to clean and maintain, but that is not the only thing that you need to look out for.

two spotted cory catfish in sandy rocks
Image Credit: Dimitris Leonidas, Shutterstock

Shallow Beds

Shallow beds usually produce a more natural look in a tank, plus they leave more room for water, plants, and fish. Shallow beds look better, but when it comes to housing a lot of plants and decorations, they may not be ideal.

Deeper Beds

Deeper beds, due to a larger volume of sand and increased depth, are better for anchoring down larger decorations and objects, plus deeper beds are better for tanks that have a lot of tall, large, and heavy plants in them. Deeper beds can suffer from the problem of methane and carbon dioxide buildups, but that can be solved with some simple stirring of the sand.

Consider Adding Sand Stirrers

One thing that you will want to consider is adding some sand stirrers to the tank. No, we are not talking about any kind of mechanical thing here. We mean live creatures that burrow in the sand, thus stirring it around, which as you can see, due to gas buildups and other health reasons, is fairly important.

You might want to get some hermit crabs, other crabs, snails, gobies, and wrasses because they all help to stir up the sand and keep it mixed, thus also releasing gasses. Just on a side note, if you do get burrowing fish, they like deeper substrate.

One of the biggest benefits of having a deep substrate layer is that it provides more room for microorganisms to grow. The deeper the sand, the more room there is for these beneficial creatures to thrive.

white spotted hermit crab in shell walking along sand in tank aquarium
Image Credit: Zuzha, Shutterstock

Making the Calculations

Okay, so figuring out how much sand you need to have for your aquarium is easily done with a sand calculator. Simply go online and find a sand calculator like this one, enter the required info, and you will be told exactly how much sand your aquarium needs. However, we can explain the process to you. For example, let’s work with a 55-gallon tank with dimensions of 12.25 inches by 48.25 inches.

If you use the sand calculator, you will be told that in order to form a 1-inch bed, you will need roughly 24 pounds of sand. So, now you need to figure out how deep you want the bed to be.

If you want the bed to be 5 inches deep, you will need to multiply that number (24) by 5, which would mean that you need 120 pounds of sand to form the layer of substrate that you need for a healthy tank.

aquarium plant divider

Final Thoughts

There is really not much to it. If you know what the inhabitants of your tank want and need, calculating the depth of the required sand bed is easy. Once you know how deep you want the sand bed to be, simply use an online sand calculator to find out how much of it you will need.

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