How to Choose Reef Aquarium Sand

How to choose Aquarium Sand

A sand bed plays a vital role in most reef aquarium set-ups. Most reefers love the look of having sand and also understand how important a sand bed is to the biological filtration of the system. However, some successful hobbyists forgo sand altogether. This article will help you decide what type of aquarium sand makes sense for you and your aquarium.

What is Reef Aquarium Sand?

Reef aquarium sand is the layer of substrate or material used on the bottom of a reef aquarium. A thin layer of sand is generally only decorative. However, a thicker layer of sand acts as a biological filter, helping consume organic matter left behind in the sand. Some sands, like aragonite, release carbonate back into the water, helping keep the pH in balance. Aquarium sand is usually made from minerals like aragonite, crushed coral, or quartz or manufactured artificially from a silica base. It comes in a variety of shapes, sizes, and colors.

Types of Reef Aquarium Sand

Most aquarium sand is live or dead/dry.

Live Sand

Live sand is filled with nitrifying bacteria and other microorganisms. Most live sand is harvested from the wild or seeded by wild sand to gain beneficial bacteria.


  • The nitrifying bacteria consume harmful ammonia and aid in cycling the aquarium.
  • The microorganisms within the sand are a food source for some types of fish and invertebrates.


  • Expensive
  • May contain hitch-hikers or unwanted pests

When it Makes Sense to Use Live Sand

Using live sand will speed up the cycling process and get the tank ready for livestock in a shorter period. Additionally, using live sand will cut down on early tank maintenance and help create a healthy and diverse ecosystem.

Reef Aquarium Live Sand
Reef Aquarium Live Sand

Dry Sand

Dry or dead sand is free of bacteria or microorganisms. This sand is often harvested; however, it is sterilized to ensure that no live organisms or hitchhikers survive and make it into the aquarium.

Reef Aquarium Dry Sand (Image Courtesy of MarcoRocks)
Image Courtesy of MarcoRocks


  • Less expensive than live sand
  • More shelf-stable and does not need to be kept in a moisture-sealed package
  • Can be rinsed or cleaned before being used


  • Takes longer to cycle an aquarium
  • May increase the presence of algae when it is first added to the tank
  • Can make the tank cloudy even if rinsed

When it Makes Sense to Use Dry Sand

An ideal choice for those who want to be extremely careful about the microorganisms that enter their systems. For those who plan to keep susceptible livestock, dry sand is a great way to prevent unwanted pests or microorganisms from entering the system. It is also generally much cheaper than live sand.

Types of Reef Aquarium Sand Comparison Chart

Type of SandPresence of Micro-OrganismsSpeed of CyclePrice
Live SandLarge amounts of micro-organismsThe active bacteria in live sand
help speed up the cycling process
Dry SandDoes not contain any live micro-organismsThe lack of nitrifying bacteria
slows down the tank cycle
Types of Reef Aquarium Sand Comparison Chart

Reef Aquarium Sand Options

Aquarium sand is available in a variety of colors and grain sizes.


Color is mostly an aesthetic preference, with most hobbyists buying sand that is some sort of beige. The lighter the sand, the more light will reflect and illuminate your coral’s underside. In recent years, black varieties of sand have become increasingly popular due to their ability to make corals pop. This is an effective way to prevent shading and promote even growth.

Grain Size

Water flow is the most critical factor when determining the proper grain size. Small grain sizes of 2 millimeters or less on average, and you risk blowing sand all over the tank. Suspended sand will make the water cloudy and damage powerheads, return pumps, and skimmer pumps. We recommend sand with a large granule size or a bare-bottom tank for high flow systems.

Do I Need to Use Reef Aquarium Sand

While having sand in your aquarium creates a more authentic representation of an actual ocean environment, it is not the best choice for every aquarium. In addition to the aesthetic benefit, a sand bed provides an additional layer of biological filtration to the system.

Pros of a Sandbed:

  • Creates an authentic ocean reef environment
  • Provides a home for beneficial bacteria that aid in biological filtration
  • A home and hiding place for livestock that lives or burrows within the sand
  • Provides additional stability to the rockwork

Cons of a Sandbed:

  • Can trap large amounts of organic material that can lead to a nutrient explosion
  • Susceptible to algae growth
  • Fine or light sand can be picked up by the flow within the tank and potentially damage pumps and other equipment.
  • Unwanted microorganisms or hitch-hikers can inadvertently enter the aquarium along with the sand
  • Requires regular cleaning and maintenance

If you’re trying to boil down your sand vs. bare-bottom decision to a few key factors, consider the following:

  1. Will your system require large amounts of flow? If so, we suggest going with a bare-bottom setup.
  2. Do you want to cycle your aquarium fast? If so, we suggest going with a live sand setup.
  3. Do you like the look of sand but want to prevent any hitch-hikers from making it into your system? If so, we suggest going with a dry sand setup.

Sand Recommendations for Common Aquariums Chart

Aquarium TypeSand RecommendationAmount of Sand RecommendedReasons for Recommendation
55 Gallon Mixed ReefCaribSea Arag-Alive Live Sand50 Pounds for a 1.5-2” SandbedFor a standard mixed reef, live sand will speed up the cycling process
90 Gallon SPS DominantBare-BottomN/AFor a high-flow SPS dominant tank, consider forgoing the sand
120 Gallon Fish-Only TankCaribSea Aragonite Special Grade Dry Sand100 Pounds for a 1.5-2” SandbedIn a fish-only tank, dry sand will quickly transition into live sand
Sand Recommendations for Common Aquariums Chart

How to Add Reef Aquarium Sand to Your System

Preparing sand for use within your aquarium will vary slightly depending on the type of sand. For example, dry sand needs to be repeatedly rinsed before adding it to your system, whereas live sand should not be rinsed. If you are getting ready to add sand to your system, we suggest referring to the following steps.

  1. Purchase the proper amount of sand for your system. Use a sandbed calculator if needed.
  2. Rinse dry sand until the water is clear. Avoid/skip this step for live sand.
  3. Add the sand to the aquarium and even it out.
  4. Place a plate or bowl on the sandbed and add water directly to the plate or bowl to avoid disturbing the sand.
  5. If available, add a water clarifying packet. For live sand only.
  6. Let the sandbed settle with very minimal water flow. The aquarium should be pretty clear 24 hours later.

Final Thoughts on Reef Aquarium Sand

We hope this article helped you grasp whether or not a sandbed is a good choice for your aquarium. Most of the sand selection process is dictated by your personal preferences. If you have any additional questions about sand for an aquarium, please contact our support team.