Sand in Freshwater Aquariums: What to Know Before You Start
Thinking about using sand in your freshwater tank? Gravel might be the go-to for most beginners, but sand is a close second because of its natural look and compatibility with certain fish. Just like with any substrate, sand comes with its own unique pros and cons to consider. In this guide, we’ll walk you through how to choose the right kind of sand, whether it works for planted tanks, and what it takes to keep it neat and clean.
What’s So Great About Aquarium Sand?
One of the biggest advantages of using sand as a substrate is its clean, smooth appearance and natural aesthetic. Many aquascapers use sand to design eye-catching layouts, such as winding paths that weave between dense fields of green foliage. Plus, certain fish species display unique behaviors on sand — such as Geophagus eartheaters cichlids sifting for food, shell dwellers digging out the perfect den, or loaches burying themselves underground.
Sand is also commonly used to cap aqua soil or organic dirt in fish tanks. These nutrient-rich substrates can cause pH swings and release excess nutrients in the water, so a decent sand layer of 1–2 inches (2.5–5 cm) on top helps to lessen the impact on water chemistry. Normally, sand is completely inert, meaning it won’t alter your water parameters, but special varieties like aragonite or coral sand can help raise the pH and hardness, making them ideal for African cichlid tanks.
A common question among fishkeepers is whether sand or gravel is the better choice. Honestly, it comes down to personal preference. Some hobbyists like the pebbly appearance of gravel and how the small gaps between the pieces trap debris beneath the surface. However, others prefer the uniform, polished look of sand and choose to vacuum up any visible waste to keep their aquarium floor looking neat and pristine.
Can You Grow Aquarium Plants in Sand?
Yes, you can, but it depends on the type of plants you’re trying to grow and how they absorb nutrients. For plants that primarily take nutrients from the water column — such as floating plants and rhizome plants like anubias — sand is not a problem. In fact, these plants don’t even need to be planted in substrate and can live in bare bottom tanks.
However, growing root-feeding plants (like Amazon swords, cryptocoryne, and certain bulb plants) in sand can be a little more challenging. Normal sand is inert and doesn’t have any of the nutrients these species need to thrive. Some options to keep your plants heathy and strong include:
- Regularly inserting root tab fertilizers into the sand to feed the plants
- Using a layer of nutrient-rich plant substrate on the bottom and capping it with 1–2 inches of sand to help anchor the plants in place
For the best chance of success, pick a larger-grain sand with some gaps between the particles so the growing roots have more space to spread out. It’s not uncommon for newly planted plants to float up or not stay in place, so try inserting rooted plants about 1.5–2 inches into the sand and plunge stem plants as deeply as possible using planting tweezers. You can also weigh them down with plant weights or wedge them between small rocks to hold them in place until the roots get more established.
Choosing the Right Type of Sand
Not all sand is created equal. There are many colors, grain sizes, and other features to choose from. As you’re shopping for the perfect sand, make sure to check for the following:
- Is it labeled as “aquarium-safe”?
Use sands specifically made for freshwater aquariums. If you're considering sand intended for other uses, check the rest of the list to make sure they won’t harm your fish. - Is it inert or chemically neutral?
For most freshwater aquariums, we don’t want any sands that contain calcium carbonate and other minerals that change the water parameters. However, if you’re keeping species that prefer high pH and GH, then pick a good sand intended for African cichlids that will help maintain the right hard water conditions. - Is it clean or pre-washed?
Some substrates are labeled as “pre-washed” or “no rinse,” especially if they contain live beneficial bacteria or plant nutrients. If not, you’ll need to wash the sand (without soap) to remove fine dust and prevent cloudiness in the water. - Are the sand particles smooth and safe for fish?
Avoid sharp, jagged sand that may harm your bottom dwellers. Nice, rounded grains are the safest bet. - Is the color coating or dye safe for aquariums?
Stay away from craft or decorative sands with artificial colors unless they’re specifically made for aquarium use. - How big are the sand grains?
We usually recommend picking a larger grain around 0.5 mm or more for easier cleaning, clearer water, and healthy rooted plants.
How to Wash and Prepare Aquarium Sand
Washing aquarium sand is a lot like rinsing rice before you cook it. Start by grabbing a clean, 5-gallon bucket — one that’s never been used with any soap, cleaning solutions, or toxic chemicals — and head outside to an area with a garden hose.
- Add sand to the bucket until it’s about one-fourth to one-third full.
- Place the hose at the bottom of the sand and turn on the water. Let the water stir up the sand. If the water pressure isn’t strong enough, manually mix it with your hand or a wooden spoon.
- Once the bucket is full of water, carefully tip the bucket to pour off the dirty, cloudy water floating on top.
- Repeat Steps 2–3 about three to four times until the water stays fairly clear after stirring.
- Once rinsed, pour the clean sand into the aquarium, and start rinsing the next batch of dry sand.
A sand bed of about 1–2 inches is plenty deep for most freshwater tanks, but you can add more if you have certain species like shell dwellers that enjoy digging. Once you have enough sand in the tank, place a plastic bag, plate, or shallow bowl on top of the sand. Pour water onto it to fill the aquarium, which softens the impact and minimizes cloudiness. If you’re adding sand to an existing tank, lower the water level first and use a large cup or scoop to carefully pour the sand where you want it.
How to Keep Sand Clean in Your Aquarium
Sand has a reputation for being hard to clean, but it’s really just a little different than gravel. Instead of sticking the gravel vacuum straight into the sand, hover it just above the surface so that the debris gets pulled up without removing too much sand. You can also gently swirl the end of the vacuum over the sand to stir up the lighter waste, making it easier to siphon away. If you’re still sucking up too much sand, try switching to a narrower aquarium siphon with a 1-inch tube to lower the suction power.
For heavier, larger-grain sand, you can plunge the gravel vacuum into the ground, and the sand usually falls back out if you lift the tube high enough off the ground. (Just don’t go too deep if you have nutrient-rich substrate with a sand cap on top, or else it may disturb the layers.) You can also kink the hose to temporarily slow or stop the suction, which allows the sand to fall out. If you find that mulm (the fluffy, organic debris that naturally settles in your tank) is accumulating in hard-to-reach corners of the tank, you may need to remove some of the decorations or hardscape occasionally for a deeper clean.
Over time, if your white or light-colored sand begins to discolor, just siphon off a thin layer of sand off the top and replace it with new sand. If you find that aqua soil particles are getting mixed with the sand, use a small siphon to suck up the mixed substrate. Then strain it through a coarse fish net resting in a container of water. The sand will pass through the net into the water, while the larger aqua soil pieces stay in the net. Some hobbyists even use a rare earth magnet to remove stray bits of aqua soil that contain iron.
Final Thoughts: Sand Is Easier Than You Think
Aquarium sand might seem intimidating at first, but with the right prep and care, it can be just as beginner-friendly as gravel and offers a beautiful, natural look. If you're ready to get started, explore our selection of aquarium sands to find the perfect fit for your setup. For more helpful tips on aquariums and plant care, check out our related articles below and subscribe to our weekly newsletter to stay in the loop!
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