February 25, 2020

Aquarium Gravel & Sand For Your Fish Tank

fish tank gravel benefits

The substrate is a core element of your aquarium set up. It is not only important for aesthetic reasons, but also for the health and well being of your fish and plants.

Choosing the right substrate for your aqua one fish tank can be a little confusing. There are so many different materials and sizes to choose from.

There are substrates that promote bacterial balance, encourage plant growth or discourage dust and algae build up, and options that do all or none of the above while glowing in the dark or just looking pretty.

I’m guessing that you’d rather not spend hours and hours trying to figure out which substrate to buy. That’s why we have put together this complete guide to choosing the right type of substrate to meet your needs.

So, If you want an aquarium that looks good, is easy to clean and is suitable for your fish and or plant-life then don't worry, we've got you covered.

Should You Use Aquarium Gravel or Sand?

Unsure whether you should be using aquarium gravel or sand in your tank?

This is one of the questions that we get asked most frequently. So let's dive in (pun absolutely intended!) and look at both of these options in a little more detail.

The Benefits Of Aquarium Gravel

Aquarium Gravel

One of the key benefits of choosing aquarium gravel is that it allows the water to run through it. This is important because it stops amoebas and bacteria from building up too much in the substrate.

If left unchecked, harmful bacteria can cause your fish to become ill and unsightly mould to accumulate within the tank.

Because of its weight, gravel is also much less likely to get drawn up into and therefore clog up the filters in your aquarium. This is a frequent problem with using aquarium sand.

Another of the main reasons that you might choose gravel over aquarium sand, is that gravel offers a far greater scope for creativity. There are lots more colours available, which allows you to customise your aquarium to your exact liking.

If bright colours and glow-in-the-dark are your thing, you can create a fluorescent wonderland using glow in the dark substrates like this one from Glofish.

Glofish substrates are great. I call them “goldilocks gravel” because they are not too big that they look odd and not so small that the vacuum will suck them up.

This one mixes three different fluorescent colours (blue, pink and green) that respond to your aquariums blue lighting. You can use it as your main substrate or as an accent to add a pop of vibrant color.

Alternatively, If you don't want to mix gravels then you can get one like this that has a dark base and which already has 4 different fluorescent accent colours mixed in.

With Glofish gravels you should aim to buy 2 pounds of gravel per gallon of water. They don't seem to need as much rinsing as some other brands of gravel.

It's a good idea to consider how visible your fish will be against the colour that you have chosen. If you have a dark coloured fish and dark coloured sand or gravel, then you may not be able to see your fish very well.

If your fish are brightly coloured then you may want to use gravel in a neutral colour like black, grey or white. One of my personal favourites is this white frost gravel.

It gives you a clean minimal look which really makes the colours of your fish, plants and accessories stand out. It is also fluorescent, which increases the vibrancy of the white. You can also get the exact same gravel in black if you prefer:

Another way of getting your fish and plants to stand out against the substrate is to use a contrasting colour palette.

If you prefer a contrast, some good colour combinations are orange and blue, yellow and purple or red and green.

Aquarium Gravel - Bad Points

Dust is a common problem with some gravels. If you decide to go with gravel, make sure you rinse it thoroughly several times before adding it to your aquarium.

You need to do this so that you don't get little dust particles in your tank, as this will greatly reduce visibility and is not good for the health of your fish.

There are some gravels on the market that are pre-soaked and therefore don't need to be rinsed. If you want to save the time and trouble it takes to clean your gravel, you can opt for a product like this one, which is dust free and non-toxic:  ⬇️

Marina Decorative Aquarium Gravel, 450 g, Rainbow
  • Provides optimum surface for beneficail bacteria colonization.
  • Epoxy-coated gravel safe for aquarium water.
  • Helps maintain clear and healthy water.
  • Dust free
  • For fresh and salt water

Another problem with gravels is that they can make it difficult to maintain the pH level. A lot of gravels, particularly coloured ones, cause the pH levels of the water rise. Whether this is a concern for you depends on the type of fish that you are keeping.

Some fish like goldfish, guppies and mollies, for example, are fine in high alkaline water. Others, like most species of freshwater fish, do not do well in high alkaline or hard water.

If you are concerned about maintaining pH levels you might want to steer clear of the coloured gravels and opt for a gravel that is more natural, like this: ⬇️

Marina Decorative Aquarium Gravel Natural Desert Pebble, 2 - 4 mm, 2 Kg, Beige
  • Marina decorative aquarium gravel natural desert beige pebble
  • Completely natural gravel for charm in your aquarium
  • Will not affect water chemistry or harm your fish
  • Excellent substrate for natural plants
  • Provides solid ground for securing accessories such as ornaments

This one is completely natural and should not affect the chemistry of the water or cause harm to your fish. It's also suitable to use with plants and provides a good foundation for ornaments. ⬇️

Marina Decorative Aquarium Gravel Natural Beach Pebble, 12 - 18 mm, 2 Kg
  • Marina decorative aquarium gravel natural beach pebble, 2kg, 12-18mm
  • Completely natural gravel for stunning beauty in your aquarium
  • Will not affect water chemistry or harm your fish
  • Excellent substrate for natural plants
  • Provides solid ground for securing accessories such as ornaments

This one is much larger, at 12 to 18 mm. It is also a natural and safe option in terms of water chemistry. Don't be confused by the name, it is not pebbles, it is a gravel. The name Natural Beach Pebble is a reference to the colour, not the size. ⬇️

Natural Color Aquarium Stones Pebbles Substrate Gravel, 0.5 - 1 cm, 5 kg
  • Suitable for Fish and plant
  • Great addition to any aquarium, fresh or saltwater
  • These are very decorative and will look amazing in any aquarium setup
  • An excellent hobby and craft material
  • It can be used for general gardening purposes

If you still want natural gravel but you prefer a little bit more colour then these might fit the bill. They are suitable for fresh and saltwater setups, and if you have any left over, you can pop them into your plant pots!

Can Aquarium Gravel Harm My Fish?

Everyone loves corydoras, there are hundreds of different species to choose from and the fact that they don't cost much makes them very popular.

However, some commonly kept fish like corydoras can find it difficult to feed on gravel, and some sharper gravels can actually damage or wear away the barbels near the front of their mouths.

Species that filter through the substrate in order to feed will find it much easier and more comfortable to do so with sand.

Similarly, fish that like to burrow into the substrate such as the kuhli loach, for example, should always be given aquarium sand so as to avoid them damaging their sensitive stomachs.

If if you have catfish, carp, goatfish, hagfish sturgeon or similar, then you’ll need to buy either a very fine gravel that is specially designed to be suitable for fish with barbels, like this one: ⬇️

Roman Gravel White Quartz Sand 8 Kg
  • Suitable for all types of Aquariums including coldwater, tropical and marine
  • Increased surface area allows for improved anaerobic activity
  • Makes the perfect planting medium due to its finer size
  • Suitable for bottom feeders and barbed fish

Or simply use a sand based substrate instead.

The Pettex Roman gravel is a good all-rounder that’s suitable for cold water, tropical and marine aquariums. It’s safe to use with barbed fish and bottom feeders and is also suitable for planting.

This is also a very bright, white, ultra-fine gravel sand that rivals some of the world's most desirable beaches!

What Are The Benefits Of Using Aquarium Sand?

It's very important to keep the pH levels in the tank balanced and stable. Tanks that use aquarium sand seem to need less pH adjustment. If you use aquarium gravel the pH level of the water will be quite high So this is something that you need to be aware of and that may need adjusting. You can buy pH balancing solutions that will do this.

When you have corydoras, loaches or even molluscs (such as clams) in a tank with sand, your tank will be a lot cleaner because the sand will be constantly turning over as they feed. This helps to keep bacteria build up (from bits of uneaten food for example) at a minimum. It also prevents algae growth.

This isn't a big problem, but it does mean that aesthetically speaking, aquariums with sand substrate tend to look a little bit better for a little bit longer. If you want your aquarium to have a clean minimalist look, then sand may be a better choice. Alternatively, you can also add shrimp to your gravel-filled tank to help keep it clean and algae free.

If you're concerned about bacteria build-up, you might consider buying a substrate that promotes the growth of healthy bacteria and reduces the amount of undesirable debris like this one from Imagitarium

This substrate helps to replicate a positive natural environment by facilitating the growth of beneficial bacterias that break down waste. It’s suitable for freshwater and saltwater fish and one bag should be enough to cover a 40-gallon tank well. It also looks really good in the tank, just remember to rinse it well before you use it.

So, generally speaking, and is more appropriate for certain species such as those with barbels mentioned above. In addition, as a general rule, plants (especially grassy plants) tend to do slightly better in sand than in gravel. Sand also looks a bit cleaner than gravel. Having said that, the difference in cleanliness is minimal and you will be absolutely fine using gravel if that's what you prefer.

What Are The Cons Of Using Aquarium Sand?

The main downside of using aquarium sand is that it can clog up your filters.

Aesthetically, sand is not as versatile as gravel.

Also, if you decide to use a suction cleaner you will undoubtedly lose a bit of little bit of sand when cleaning.

While aquarium sand doesn't allow the water to flow through it as well as gravel does, this does not matter too much if you have bottom feeders or burrowing fish, as they will sift through the sand to find food which will promote cleanliness.

Using An Aquarium Gravel Cleaner On Your Tank

Before you add any gravel to your aquarium you should ensure that it is completely free of dust and dirt. The best way to do this is by putting small amounts into a clean bucket and spraying it down with a hose pipe.

You can also clean gravel in a bucket using the shower if you don't have a hosepipe.

Cleaning gravel can be tedious and very messy. This is why there are a lot of products on the market that are dust free (see the cons of using gravel section above for our recommendation for a dust free gravel).

Once your gravel is inside the tank. You will need to clean it regularly as part of your normal cleaning cycle.

Some gravels can be difficult to clean. Although there are some great products on the market that are specially designed to clean gravel, even if you're using a specialist cleaner like this Zacro one: ⬇️

Zacro Aquarium Fish Tank Cleaner, Vacuum Siphon Water Pump Gravel Sand Cleaner, Aquarium Water Filter with Flow Control Tap
  • Extra Long & Durable: Total length is 253.8cm. It come with two soft hose (130cm + 44.5cm) which is 2mm thick and one hard tube 34.5cm.
  • Big Airbag: Water can be suck out easily by squeeze the big airbag gently.
  • Flow Control Tap Design: The faucet at the end allows you to better control the flow of water and clean the aquarium, avoid sucking out the gravel or little fish due to large flow.
  • Free Adjustable Hose Holder: A hose holder for clip on the fish tank to fix the hose. It can be adjusted according to the thickness of the fish tank, and hold the hose firmly without slipping, making fish tanking cleaning easy.
  • Easy to Install & Use: Just connect all the accessories together one by one, it also come with a manual. It is ideal for water changing and gravel cleaning, giving your fish a nice living environment.

You will find that there is still some algae present after cleaning. Therefore It's a good idea to use a gravel cleaner like the one above in conjunction with a bacterial treatment like this one from Evolution Aqua. ⬇️

Evolution Aqua Pure Aquarium - for a Crystal Clear Healthy Aquarium (50 balls)
  • NATURAL, CHEMICAL FREE SOLUTION FOR A CRYSTAL CLEAR, HEALTHY AQUARIUM – Pure Aquarium contains beneficial bacteria and natural enzymes that rapidly break down organic waste leaving your aquarium clean and fish healthy.
  • REDUCES FILTER AND TANK MAINTENANCE – By naturally removing excess fish waste, fish food and toxins, Pure Aquarium helps your water stay fresher for longer, meaning fewer tank maintenance sessions and happier, less stressed fish.
  • CONTINUOUS GRAVEL CLEANING AND WATER FILTERING ACTION – Simply adding 1 to 2 Pure Aquarium balls per 25 litres of water once a week, Pure Aquarium reduces sludge and organic build up on gravel ensuring that your fish can thrive in a safe, healthy and crystal clear environment.
  • SAFE FOR ALL FISH AND TANKS – Pure Aquarium’s all natural ingredients only activate when needed and are safe to use in new or established aquariums.
  • AWARD WINNING PRODUCT, MANUFACTURED IN THE UK – Twice awarded product of the year by Practical Fishkeeping.

Whether you have a tropical or freshwater aquarium, using a purifier like this one helps to control ammonia and nitrate levels, keeping the water healthy and clear.

It also reduces the amount of cleaning and maintenance you need to do on your gravel and filters. You should add 5 to 10 balls per 100 litres of water for the best results.

Siphon gravel cleaners like the Zacro one above help to get rid of the dirty water that lurks within the substrate. You should use it weekly when you do a partial water cleanse. Syphon filters work by sucking up the gravel grains and swirling them around to remove the dirt and debris.

If you want to replace your substrate with something a little more attractive. Or you just fancy a change, then having a syphon cleaner can come in handy.

Siphon cleaners, when fitted with a larger hose, for example, can also be used to remove the unwanted substrate. This means that old substrates can be replaced without you having to empty out the whole tank.

If you are using a siphon powered gravel cleaner, you will need to get it started. A lot of people have trouble with this, and the most common method to get your filter going is to suck on the end of the hose.

This method is the quickest and most commonly used strategy, which is fine if you don't mind risking a lungful of horrible aquarium water.

However, if you prefer a more hygienic method, try putting your thumb on the end of the hose and holding the attachment on its side in the tank.

Take your thumb on and off a few times (you'll need to be quick) and the hose should start to fill. When both the hose and the attachment are full of water, position the end of the hose over a bucket and take your thumb off. This technique should get the water flowing by itself and save you from sucking up dirty water!

Another good tip to keep your aquarium tank clean and algae free is to get yourself a magnetic fish tank glass cleaner. They don't cost much, are suitable for glass, acrylic and plastic tanks, and I really easy to use. This one has great reviews and is good value. ⬇️

EZONTEQ Fish Tank Cleaner Brush Scraper, Floating Magnetic Aquarium Fish Tank Glass Cleaning Tool with a Free Filter Sponge for Aquatic Algae Cleaning
  • 🍃 SUITABLE FOR ALL KINDS OF TANK: The magnetic fish tank brush is suitable for all kinds of tank, such as acrylic, glass or plastic etc. that does not degauss
  • 🍃 STRONG MAGNETISM: The magnet is strong enough as to stay attached even when you have non-standard type tanks, and can prevent weting hands when trying to retrieve the submerged part.Please note: make sure that the glass thickness is less than 5mm, and the fish tank should not be too large, otherwise the brush magnetism of the fish tank will be weakened
  • 🍃 SHIFT ALGEA WITH EASE: Put the flat part into the aquarium tank, put the other part outside of the tank and they can be adsorbed together. Move the outside piece and the inside one will move likewise, thus, you can clean inside and outside of the aquarium tank at the same time
  • 🍃 FLOATING DESIGN: The internal floating avoids the brush(the part in tank) sinking in the bottom of aquarium and makes it convenient to take it out of the tank
  • 🍃 GET ONE FILTER FOR FREE: The magnetic tank cleaner comes with one sponge filter free of charge

How Do I Clean Aquarium Sand?

Once a week you need to swish around the aquarium sand in your tank, just do this manually and you will release all of the organic debris into the water. Let the debris settle, then use an aquarium cleaner like this one ⬇️

Zacro Aquarium Fish Tank Cleaner, Vacuum Siphon Water Pump Gravel Sand Cleaner, Aquarium Water Filter with Flow Control Tap
  • Extra Long & Durable: Total length is 253.8cm. It come with two soft hose (130cm + 44.5cm) which is 2mm thick and one hard tube 34.5cm.
  • Big Airbag: Water can be suck out easily by squeeze the big airbag gently.
  • Flow Control Tap Design: The faucet at the end allows you to better control the flow of water and clean the aquarium, avoid sucking out the gravel or little fish due to large flow.
  • Free Adjustable Hose Holder: A hose holder for clip on the fish tank to fix the hose. It can be adjusted according to the thickness of the fish tank, and hold the hose firmly without slipping, making fish tanking cleaning easy.
  • Easy to Install & Use: Just connect all the accessories together one by one, it also come with a manual. It is ideal for water changing and gravel cleaning, giving your fish a nice living environment.

to suck up the top layer of debris. You need to be careful when doing this so that you don't suck up too much of the aquarium sand. A good tip is to hold it about an inch above the debris.

The Zacro cleaner recommended above has a 2mm thick hose which is perfect for cleaning sand as well as gravel. It also comes with a good length of hose (130 cms) which makes the job a lot easier.

What Is The Best Substrate For My Plants?

Specially enriched substrates allow plants to root themselves more easily. They are beneficial for providing nutrients and also for reducing algae growth. You can use plant-specific substrates either on their own or as a layer underneath gravel or aquarium sand.

If you like to have natural plants in your aquarium, you'll need a substrate that allows them to thrive. This Eco-complete substrate from Carib Sea contains volcanic soil. The soil is full of minerals to help keep the plant life in your aquarium healthy. This particular gravel has small pieces which shouldn't harm corys or similar. It's also low maintenance and looks great.

You don't need to rinse this before you use it, just put it straight into the tank. To fill a 20 L tank (measuring 30 x 20 inches) to a depth of approximately 2 1/2 inches you will need 3 bags of this.

What Is An Inert Substrate?

During your research, you may have come across the terms “inert” and “non-inert” substrates. But what do these terms mean exactly?

In basic terms, any substrate that does not alter the chemistry of the water can be considered inert. So if a substrate is inert, there is no need to adjust the pH level of the water when you add it.

Non-inert substrates, on the other hand, will significantly affect the water’s pH balance, usually increasing it and making it more alkaline.

Adding a non-inert substrate to your tank will harden the water. This is due to the presence of calcium and other minerals that are present in the substrate. It's important to be aware of this because while some species of fish can live in hard water quite happily, others cannot.

To avoid harming your fish, always check the requirements for each of your species. Do this before adding any type of substrate to your aquarium.

How Much Substrate Should I Use?

Generally speaking, with gravel, you are looking to create a depth of approximately 1 1/2 to 2 inches. With aquarium sand, you can get away with slightly less, say around 1 inch.

Depending on the type of plants you are using you may wish to increase this slightly to allow for root growth.

Calculating the right amount to get is difficult. This is because substrates are sold by weight, and we're trying to find out how much to buy to create the correct volume.

You can, however, work out how much substrate you will need by following these simple steps:

  1. Measure the length and width of your tank in inches (eg 20” x 40”).
  2. Multiply the two figures together (eg 20 x 40 = 800).
  3. Divide your answer by 10 (eg 800 divided by 10 = 80).
  4. Divide your answer by 2.2 (in order to convert it to kilograms)

So, for the example, 80 divided by 2.2 = 36.3 kg of substrate required.

So, now you know everything there is to know about choosing a good substrate. I hope that you have found the information in this guide useful. Hopefully, you now feel much more confident in choosing the correct substrate for your aquarium.

Have fun designing your aquarium and I wish you many happy hours of relaxation as you enjoy your creation.

What Is The Best Option For Tropical And Cold Water Tanks?

When it comes to cold water or tropical tanks, both aquarium gravel and sand are good to use. You can have a tropical tank full of gravel or a cold water tank full of sand and vice versa. It's entirely up to you.

However, if I was going to make a recommendation, I would suggest that gravel is slightly more suited to cold water tanks and that aquarium sand is marginally more suited to tropical.

The reason I say this is because cold water fish, like goldfish, for example, tend to be messy eaters and a gravel substrate with an under gravel filter provides the best filtration and keeps the water clear and free of bacteria.

Last update on 2023-11-29 / Affiliate links / Images from Amazon Product Advertising API

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