A great aquarium acts as a miniature ecosystem, a place where a multitude of organisms can survive and thrive with minimal intervention. When it comes to designing your aquarium space, the most important place to start is with your substrate. The substrate provides a harbor for beneficial microbes and bacteria, anchors aquarium plants and can create a more natural atmosphere for your fish.
Many fish hobbyists gravitate towards sand as a great aquarium substrate. It can replicate many natural environments, is great for planting, and can be layered with other substrates to provide biological filtration. It can be tricky to find the best aquarium sand substrate with so many available options on the market, but there are some things you can look out for to find the best substrate for your needs.
How to Choose the Best Aquarium Sand
Sand is regarded as one of the best substrates for your aquarium for many reasons. It replicates more natural habitats, can be easier to clean than gravel or other substrates, and provides fish with opportunities to sift and burrow. However, when it comes to sand, there are several things to keep in mind. Sand that comes from the local beach or river bed can’t be added to your tank- it would be disastrous for your ecosystem. Similarly, you want to make sure that the aquarium sand substrate you choose is of great quality.
Live sand
Some types of aquarium sand substrate are “live”, which means it comes mixed with beneficial bacteria and microbes that can help establish a bacterial colony in your tank. These microorganisms help maintain the ecosystem by breaking down waste and helping keep the tank cleaner with biological filtration. This is primarily seen in sand substrates designed for marine tanks, where establishing a balanced tank can be more difficult than with freshwater. These substrates come packed in salt water to keep the bacteria alive in transit, and should not be rinsed prior to entering the tank in order to preserve the bacteria.
pH levels
Most aquarium-rated sands are inert and will be guaranteed to not affect the pH level of your tank, which is extremely important in maintaining your habitat. Avoid sand that does not have this guarantee, as it could mean the sand has a chemical, dye, or another coating that might throw off your pH levels. Any rapid fluctuations in pH levels can result in the death of your fish, so be sure to measure these levels carefully after adding any new substrate to your tank.
Silica bases
When sourcing your aquarium sand, it can be tempting to go for lower-cost options, such as playground sand or pool sand. While these can sometimes work, it is important to not choose a product that has a silica base. Brown algae thrive in a high silica environment and can lead to unsightly algae build-ups in your tank. If you are using an aquarium-rated sand substrate that is silica-based, it likely has a coating on it to prevent this. If you are unsure, be sure to read the ingredients list carefully.
Grain size
Aquarium sand comes in different sizes of grains, depending on the type of fish you have and your aquarium needs. Ideally, you will want to choose a grain that works for your fish’s habits (some fish even eat sand to aid in digestion), and that will support the other components of your tank, such as plants and decorations.
The size of the grain can also give style to the aquarium, and you will want something that will suit your personal taste, and support the design of any plants in your aquascape. Sand substrates can range from very fine to large and coarse such as crushed coral. These larger grain sizes function more similarly to pea gravel as a substrate when it comes to maintenance- so a smaller grain is recommended in order to maximize the benefits of a sand substrate.
Top 5 Best Aquarium Sand
1. Nature’s Ocean Bio-Activ Live Aragonite Live Sand
This live sand option from Nature’s Ocean is made for marine tanks and features Aragonite, a resource that helps remove waste products from the water such as Ammonia and Nitrates. Due to this feature, using this sand does not require you to cycle the tank before adding fish- a benefit for the eager fish hobbyist who would like to establish their tank quickly. This sand also features a live biofilm of marine bacteria that is excellent for getting your tank set up with a colony of helpful microbes to keep your ecosystem vibrant. You can find Nature’s Ocean Bio-Activ Live Aragonite Live Sand here!
Pros:
- Live biofilm adds beneficial bacteria to your tank
- Aragonite absorbs harmful waste chemicals from your tank, resulting in a cleaner tank in the long run
- The instant cycling feature means that you can add fish to your tank right away without having to cycle the water to establish your bacteria
- All-natural product means no dyes or toxins can leach into the water
- Fine-grain sand is ideal for reefs
Cons:
- Not recommended for freshwater tanks
This product is all-natural, does not contain any excess chemicals or dyes, and comes in a pleasing light tan color. The grains are 0.5-1.7 mm in diameter and are suitable for reef tanks. Although some hobbyists have used this aquarium sand substrate for freshwater aquariums, it is important to thoroughly wash the sand prior to adding it to your tank in order to remove the salt- which will also kill the helpful bacteria- so this might not be the best choice for such applications. Additionally, this sand is very fine and is not meant to be used with undergravel filter systems.
2. Seachem Flourite Black Sand
This black sand is made up of a Flourite mixture which is fantastic for planted tanks and aquascapes. This sand substrate is made specially out of stable porous clay, which provides more nutrients to plants over time and encourages root growth. It is a natural product that is not chemically treated and will not affect the PH levels in your tank. You can find Seachem Flourite Black Sand here!
Pros:
- Fluorite is great for maintaining and growing plants in planted tanks and aquascapes
- No additional fertilizers are needed to establish plants when using this sand
- It will not impact the PH levels of your tank
- Never needs replacing
Cons:
- Very fine grain can be dusty and will need preparation before adding to your tank. Once added, it will need a few days to settle
- The fine grain might be easily disturbed by animals who like to do a lot of digging and burrowing
This clay has been ground to a fine grain which creates a large surface area that is great for establishing beneficial bacteria colonies. The chemical benefits of flourite do not diminish with time, and this substrate will never have to be replaced. Due to the product being a very fine grain, it will get dusty in the bag and will need to be washed before adding to your tank, and it will need additional time to settle once it is added to the tank. Like most sand substrates, it should not be used with an under gravel filtration system.
3. CaribSea Arag-Alive Special Grade Reef Sand
This live sand by CaribSea is formulated especially for reef tanks. It features Aragonite, which is great for ridding your tank of waste chemicals, and comes with living bacteria ready to establish in your tank immediately without the need for cycling. You can find CaribSea Arag-Alive Special Grade Reef Sand here!
Pros:
- Aragonite removes harmful waste chemicals from your tank
- Established bacteria cycles instantly and gets your tank up and running faster
- Natural product with no chemicals or silica
- Included clarifier helps the water to settle more quickly
- Made especially for reef tanks, with minerals that aid in reef growth
Cons:
- Not suitable for freshwater tanks
- One of the more expensive options for aquarium sand substrate
This allows you to add the fish instantly without having to wait for the tank to cycle. This sand substrate also supplies the tank with minerals such as calcium, strontium, and carbonate to keep your reef growing and thriving. This mixture is also silica free, which prevents algae blooms from clouding up the tank. The chemical benefits of this sand do not fade over time, so this product will never have to be replaced.
Additionally, each bag of sand comes with a packet of bio-magnet clarifiers, which helps clear up your water faster. Designed for reef tanks, the grains in this mixture vary greatly in size and feature ground-up coral bits mixed in with the sand- it would not be suitable for a freshwater tank. CaribSea collaborates with public aquariums and zoos to create their substrates, and their products are often favorites for authentic and natural designs. Like most sand substrates, it should not be used with an under gravel filtration system.
4. African Cichlid Bio-Activ Aquarium Live Sand
This unique sand option is made up of special pebbles and is formulated to replicate Rift Lake environments specifically for African Cichlids. It is live sand, which means you can expect a fast setup and no cycling to prepare your tank with friendly bacterial colonies. This mix also features Aragonite, the ingredient which prevents the dangerous buildup of waste chemicals. You can find African Cichlid Bio-Activ Aquarium Live Sand here!
Pros:
- Engineered to replicate Rift Lakes environment specifically for African Cichlids
- Live sand reduces the cycling time when establishing a new tank
- Aragonite immediately reduces levels of waste chemicals
- Fine-grain sand is suitable for reef tank use
- Natural product with no dyes or chemicals
Cons:
- Silt in the sand mixture can take a while to settle and clear
The aquarium sand substrate is guaranteed to not influence the pH levels of your tank, which is great for maintaining a healthy ecosystem. The grains range from 0.5-1.7mm in diameter, which makes this product suited for reef tank use. Like most sand substrates, it should not be used with an undergravel filtration system. The product does not recommend rinsing before use to preserve the bacteria, however, this can result in some cloudy water which should clear up on its own over the course of a few days.
5. Imagitarium Black Aquarium Sand
This aquarium sand substrate is a great and affordable option with a deep black color. The substrate is pH neutral and will not disrupt the ph levels in your tank. It is synthetic sand that is rated as being aquarium safe, and will not leak chemicals or dyes over time. As a synthetic product, there is also less silt packaged into it, so very little rinsing is necessary to prepare it for use in your aquarium. Here you can find Imagitarium Black Aquarium Sand here!
Pros:
- An affordable option, so you can fill up a lot of space quickly
- A neutral product that will not disrupt the pH levels of your tank
- Less rinsing is required than some of the more silty natural options
- Can be used in both freshwater and saltwater aquariums
Cons:
- No live bacteria established
- Synthetic material might not be what you are looking for in a natural habitat
It is suitable for both saltwater and freshwater aquarium use, with a standard fine grain texture that will work for a multitude of fish. Compared to some of the other sands on this list, it is a more basic option. There are no specially added minerals or live bacteria present.
However, you still get the added benefits of using sand substrate instead of gravel, including a higher surface area which promotes the growth of healthy bacteria. The dark color of the sand is also in great contrast with colorful fish and can be a great design element in a planted tank or aquascape with lots of plants. Like most sand substrates, it should not be used with an under gravel filtration system.
Frequently Asked Questions About Aquarium Sand
There are many other brands of sand available on the market that might be better suited for your specific aquarium needs. For example, someone who is creating an aquascape might focus more on sand that will sufficiently anchor larger plants than someone who is looking to achieve a heavily stocked reef tank. It all depends on your goals for the aquarium and the needs of your fish. However, there are always questions that arise when searching for the best aquarium sand substrate that you should consider before making your choice.
How much aquarium sand will I need for my tank?
The general rule for stocking your tank with sand is 1.5 pounds of aquarium sand substrate per gallon. However, this does not take into account any of the unique factors for the individual tank. The amount of sand that you will need for your tank will vary depending on a few different aspects of your setup.
Heavily planted tanks might need deeper beds larger than one inch if the root systems require lots of space to grow. Larger objects and decorations might also need a deeper foundation of sand in order to anchor them safely and effectively. Deep beds can also provide more space for beneficial bacterial colonies to thrive. However, maintaining a thicker layer of sand does come with some upkeep.
Sand that is left undisturbed and deprived of oxygen can become an anaerobic dead zone. This situation can be prevented by stirring the sand occasionally, or by adding some fish that are natural burrowers to your tank to keep things moving.
A shallow bed of sand closer to one inch deep might be more suitable for smaller burrowing fish and smaller plants. The shape of your tank is also something to consider when purchasing any substrate, as vertically oriented tanks will have less of a surface to cover than a wide bottom tank. If your sand substrate of choice is not live, you might consider purchasing more than you think you will use, just in case.
Are there any problems associated with aquarium sand substrate?
Generally, a sand substrate is often regarded as easier to maintain and more beneficial than gravel in many aquarium setups. It is easier to clean, as large particles of waste and food cannot seep into cracks and decompose. The larger surface area also gives more space for beneficial bacteria to grow and thrive.
However, there are some things to be cautious about when using sand as an aquarium substrate. If there are deep portions of sand that do not receive adequate oxygen, it can become a breeding ground for anoxic bacteria, which release toxic hydrogen sulfide gas. This build-up can be prevented by making sure the sand is oxygenated in the same way that your water is- by moving it around.
If you do not keep fish that like to burrow and dig in the substrate, you can always give the sand an occasional stirring to keep things moving. Another potential problem with sand substrates can occur with brown algae blooms. This tends to happen when a sand substrate that is silica-based is used in the aquarium, which feeds the algae and encourages its growth.
This problem is easily avoided by selecting a silica-free substrate, and cleaning up any algae growth before it gets out of hand. Otherwise, the benefits of a sand substrate are usually considered to outweigh the potential for problems. As with any aquarium setup, adequate prevention can make a world of difference when it comes to solving problems in your tank.
Will aquarium sand clog my filter?
A clogged filter can be frustrating, particularly if the clog is bad or constant enough to cause permanent damage to your filter. It is understandable that some hobbyists can be skeptical about using sand substrate when it comes to adequate filtration.
The fine granules of sand float around longer than larger substrates such as pea gravel, causing some cloudy water and getting caught in the filter. This is really only problematic for very fine grain sand, such as silt. Filters that are placed too close to the bottom of the tank also might be prone to clogging from sucking up the sand.
If this is a concern, you should place your filter several inches higher than the substrate to avoid clogging. Aquarium sand substrates are also not appropriate to use with an undergravel filter, which would easily clog when placed under the sand. If you find that your filter is still clogging due to sand, a simple solution of thin fabric such as nylon placed over the intake for the filter might prevent future headaches.
It is worth noting that when sand is used as an aquarium substrate, the beneficial bacteria that can establish on the surface area is often considered an additional level of filtration for your tank, and might be worth switching your filter for should you run into any clogging issues.
Final Thoughts
Sand is often a more beneficial and lower maintenance choice for aquarium substrate when compared to other options such as pea gravel. With so many varieties to choose from, it can be overwhelming to make the best choices for your aquarium and your budget. Although it can be helpful to keep some of these guidelines in mind when searching for your next substrate, ultimately each fish tank is unique.
Aquascapes, planted tanks and reef tanks are all living ecosystems that are molded and designed according to your own personal taste. A substrate that might check all of the boxes for practicality might not be the right one for you if it does not suit your aquarium goals. As long as the basic guidelines regarding the health and safety of your fish are kept in mind, there are no rules for the design of your aquarium.
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