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What type of gravel to use in my aquarium?

The usage of artificial substrate and gravel is a crucial component of our home aquarium and aquarium keeping in general. The gravel we use has several advantages for the ecosystem in addition to making the tank bottom appear pleasant, though occasionally it might have the reverse effect. But which should you pick, and why?

What type of gravel to use in my aquarium
What type of gravel to use in my aquarium

Whether we're talking about pure gravel, a substrate, or the bare tank bottom, any substrate is a crucial component of your tank. They all function as display tank decorations, but more importantly, they all operate as a nursery for the development of beneficial bacteria. But you still have to decide which material to use, what size, color, and how much to add. You must keep in mind that the size and composition of the aquarium substrate can have a significant impact on both the livestock and the aquariums' maintenance requirements.

In order to understand and get a better idea of what to use, let’s start by classifying and explaining the most common types we find when we acquire an aquarium.

Aquarium Gravel & Stones

The most typical form of aquarium bottoms we discover in our neighborhood fish stores are probably gravel and small stones. Start by avoiding any gravel that has been chemically dyed because, in addition to giving your aquarium a fake aesthetic, it may also leach chemicals into the water and upset the ecosystem, which could cause fish diseases and early demise.

Except for some gravel made of calcite and limestone, the typical freshwater or seaside gravel is typically neutral and has a natural appearance. By neutral, we mean that they have no impact on the water's parameters and don't introduce substances that change those values.

The type of fish you keep will determine the size of gravel you choose; some fish suck on gravel, so choose gravel that is primarily the right size for them to avoid choking.

Gravel is great for water circulation because it allows water to readily flow between the tiny gravel stones, which fosters an environment that is favorable for the growth of good bacteria. However, the majority of the time, each gravel stone's surface is flat, which is not ideal for good bacteria. Selecting a type with a porous surface, such as crushed lava rock, is preferable. If you select a gravel substrate, it will also be slightly more challenging to remove uneaten fish food and trash from your tank. Between the stones, undesirable particles may accumulate and degrade the quality of your water.

It is also important to note that if you plan on keeping live plants in your aquarium, not all types can survive in gravel, because of the lack of nutrients.

It's also crucial to remember that not all plant species can survive in gravel because of the lack of nutrients if you intend to have live plants in your aquarium. Which brings us to the Active substrate category.

Active Substrate

It is very advised to utilize an active substrate for aquarium décor if choosing a natural style aquarium or an aquascape aquarium.

It is active, as its name suggests, and because of this, plant-specific substrates have parametric functionality. It can be used to balance the pH of the water, give plants nutrients, or just change the water's hardness as necessary. Specialized improved soils frequently make it easier for plants to take root and eventually supply the water plant roots with nutrients. Plant substrate also serves the purpose of binding nutrients in the water along the bottom layer. Nutrient removal from water reduces the likelihood of undesirable algae growth. Plant-specific substrates may also be used in place of sand or regular gravel.

In our situation, we utilize Akadama soil, which is essentially oven-baked dirt. It is an inexpensive and effective substitute for expensive active substrates, has a porous surface, looks lovely in aquariums, supplies enough nutrients for the plants, and lowers the pH while raising the gH. It is therefore ideal for shrimp aquariums.

Active substrate's undesirable downside is its brief lifetime. It ought to be replaced each year. Worst of all, most brands can leak ammonia and create a severe ammonia spike when first added to an aquarium. Therefore, one should exercise caution when utilizing such and maintain regular water changes in the beginning.

Crushed corals are a well-known form of active substrate that is not specifically tied to plants. Crushed coral or live reef aragonite substrate will increase pH levels and hardness the water in a tropical fish tank design, which is important for the majority of tropical fish species. Brackish aquariums and tanks for African cichlids, which need harder water to live, are the sole exceptions to this rule.

Dirted Tank

Some fish and aquatic species may need mud or dirt to grow and reproduce. Neon Tetras are one illustration. Most commercial aqua soils are typically more expensive than dirt. It also contains a lot of macro- and micronutrients, which promote healthy plant growth. Some filthy tanks can last for several years at a time if they are installed correctly. Dirt substrate has a slightly different consistency than ordinary substrates, which causes the water in aquariums to become more cloudy. Additionally, it releases a lot of ammonia, which is harmful to fish and plants. Therefore, additional substrate needs to be placed on top of dirty tanks.

Aquarium Sand

Sand has recently gained popularity in aquascapes and aquariums for tropical fish. Caretakers of tropical fish occasionally forget about sand. It is a fantastic substrate that doesn't present any risks when used appropriately and in the right amounts. Debris won't sink through into the sand like it does with gravel; instead, it will stay on top, making cleanup easier. Sand can only support bacterial development, but since it prevents compaction and anaerobic conditions, sand with a medium grain size works best. Plants, goldfish, catfish, and other bottom-feeders will all flourish in medium- to large-grain sand. The sole drawback of sand is the potential for anaerobic zones to develop. This can be avoided by keeping fish species that dig in the substrate and by sometimes churning the sand.

Remember to select a silica-containing sand kind. Quartz, which can be found in sand, gravel, clay, granite, diatomaceous earth, and many other types of rock, is the most prevalent type of crystalline silica. For aquariums, silica pool sand, which is used in swimming pools, is excellent. Contrary to play and blasting sands, silica pool sands are available in a wide range of hues and grain sizes.

Bare Bottom

Beneficial bacteria won't be kept in the tank's base if it has a bare bottom, which some people find problematic because they may wind up in the filter. But there are workarounds available. Some fish hobbyists believe that maintaining adequate water quality in a tank with no bottom is difficult. However, some breeders find that bare bottom tanks are useful. Some fishkeepers choose fish tanks with bare bottoms. Although bare tanks don't look as natural or captivating, cleaning can be much simpler with no substrate. For simpler upkeep, many goldfish keepers choose a setup without a substrate. It is more practical to avoid a substrate that may collect waste and necessitate additional cleaning because goldfish are quite filthy fish.

Even if this lists the most popular aquarium bottom types utilized in the hobby, we still need to determine what should be used and how much.

What you keep and your goal for the tank will have a big impact on what to use and which one to utilize. You should use more active substrate the more plants you have. Additionally, you should lean more toward the Neutral and Natural side when removing plants and switching to fish- or shrimp-only tanks.

Keeping the breeding and shrimp aside for a while, we move to the general rule. A standard substrate depth guideline is between 1.5 and 2 inches. Consider adding a little additional substrate depth if you want to grow plants with robust, long roots. Sand depth will be slightly less in order to avoid problematic anaerobic patches from forming. A sand substrate depth guideline is between 1 and 1.5 inches.

It is advised to add some crushed lava or natural gravel underneath the sand layer to make it easier for water to circulate and make it a good environment for beneficial bacteria to thrive.

To determine how much substrate your aquarium needs, you can get the tank bottom surface, divide the answer by 10 and get the Kg equivalent by dividing the answer by 2.

As a final tip, If you are keeping a tank for breeding or keeping a bare bottom tank, and you need to alter your water parameters for specific types of fish or shrimp. You can use active substrate or dirt inside your filter or in a UGF box. The quantity should be around a cup per 5 gallons of water for Akadama soil.


video about Our second Fluval rimless tank, this time for Taiwanese bee shrimp. Changing the aqua soil and converting the setup into a breeding-friendly configuration with sufficient filtration is the most crucial step.

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