When looking at most aquariums you’ll eventually notice that gravel is by far the most popular choice. Inexpensive, attractive, and large grained, it’s used for everything from planted aquascapes to saltwater setups.
But if you want to use sand, the second most popular alternative, how well will it work with aquarium plants? Are there any benefits or drawbacks to sand versus gravel?
Aquarium Plants and Sand
As it turns out, aquarium sand is a fantastic alternative to gravel. In fact, it actually has a number of advantages over gravel, making it well worth considering for your next live plant setup!
What are the Pros of Using Sand for Aquarium Plants?
Here are a few of the benefits of aquarium sand with plants:
Anchoring Capacity
When it comes to keeping aquarium plants in sand this might be one of the clearest advantages it has over gravel. Medium to large gravel grains are not very good for many plants.
Carpeting plants in particular rarely get that thick, well manicured look they achieve when using fine grained sand substrates. The gravel grains are too large and prevent carpeting plants like H.C. Cuba or Glossostigma from filling in.
Plants with delicate roots or stems are also easily damaged during the initial rooting process. It takes just the right amount of medium to large gravel grains that are just the right shape to hold them in place until the plant can root itself.
Anyone who has tried rooting aquarium plants in gravel knows how maddening it is to go through all of that effort only to see your new plants floating a few hours later. Instead of relying solely on gravel, lead plant weights help keep them in place until they have firmly established themselves!
On the other hand, sand is perfect for plant roots of all sizes. Some sandy substrates can be too fine or light, in which case you’ll need some plant weights.
However the majority provide exactly the right amount of anchorage. Sand also won’t damage fine roots or stems and won’t prevent your carpeting plants from filling in over time!
Appearance
This is more of a subjective measure. Personally, I’ve always found sand substrates to be much more attractive than gravel. There’s something to the smooth, polished look of a sandy bottom in a single natural color that gravel can’t quite match.
Aquarium plants also tend to stand out much easier against the tiny uniform grains, especially with a strongly contrasting dark sand like Seachem Flourite.
Planting sands like Flourite also have a high cation exchange capacity (CEC). A high CEC allows them to hold onto floating nutrients like fertilizers until the roots uptake them.
But for many aquarists, gravel might be the better choice in terms of appearance. It’s really up to you which you prefer for looks!
Burrowing Animals
As great as aquarium sand is for plants it’s even better for many aquarium pets! Many fish, including Stingrays, Kuhli Loaches, and Spiny Eels all love burying themselves in sandy substrates.
They will often try and replicate their natural habits in gravel aquariums. However gravel grains are sharp, heavy, and can easily injure these scaleless fish. These wounds can then become infected and lead to loss of appetite and death.
Many invertebrates, including some shrimp, snails, and freshwater crayfish also enjoy sandy substrates. Since bits of food tend to sit on top of sand it also makes feeding smaller invertebrates easier as they are often slow to find food.
If you’re interested in raising live food for your fish, aquarium sand provides an excellent habitat for freshwater worms like Tubifex and blackworms. In fact these worms act just like earthworms do on land!
They seek out decaying organic matter, eat it, and transform it into less toxic substances. By burrowing they also help keep your sand aerated and your beneficial microbes happy!
What are the Cons of Using Sand for Aquarium Plants?
Here are a few cons when using sand for aquarium plants:
Water Flow & Compaction
Flow issues are a major reason why people often prefer gravel over sand. The tight grain space of sand prevents water from flowing as freely as it does between larger gravel grains.
Also, if sand is allowed to sit for extended periods the grains can become so tight that they become nearly impermeable to many plants. There is more than enough space for roots to thread through gravel but compacted fine sand can be a problem for plants with delicate roots.
If your sand bed is allowed to get too thick and it starts to accumulate organic matter, you can run into additional problems.
This decaying organic debris can form anoxic pockets. These are zones of no oxygen where rot-inducing bacteria decompose this matter into especially toxic byproducts like hydrogen sulfide.
There they sit like time bombs until you, your fish, or some other disturbance releases the bubble of noxious matter into your aquarium ecosystem. Without swift action, you may find your fish sitting at the surface, twitching, or even dying with prolonged exposure.
This is usually a bigger problem with very deep sand beds. If you’re using less than 3 inches of sand and not overfeeding, anoxic pockets shouldn’t be an issue.
Burrowing organisms are also a great way to ensure your sand doesn’t form anoxic pockets. In freshwater tanks, burrowing snails, Kuhli Loaches, and of course, plants with their probing roots all help keep sand substrates well aerated.
Debris Sits on Top
Another downside to using sand is that large pieces of debris can’t flow into it. Gravel allows uneaten food, fish waste, plant matter, and other unsightly bits to fall in between the grains. So long as you are performing regular water changes there is no problem with this.
Your gravel maintains a much cleaner appearance as a result. Sand has no space for debris to easily sit in. Any leftover food or feces sit right on the surface.
On the other hand, debris sitting on top of your sand means it’s much faster to clean compared to gravel. Instead of having to root through it with a gravel vacuum, you can make a few quick passes right at the surface!
This also ensures your cleanup crew get to the leftover food rather than allowing it to rot unseen. So this is more of a neutral mark rather than a purely negative issue!
Conclusion
While it’s not everyone’s first choice, sand is a fantastic choice for the aquarist who has become a little bored with the gravel look. It’s cleaner, polished in appearance, and is easier when planting, allowing roots to remain unbroken, and is burrowing animal-safe!
By the way, if I’ve convinced you that aquarium plants and sand are a match made in heaven, take a look at my review of the best substrates for planted tanks! I discuss each of the best substrates out there for healthy plants, both sand and gravel!
