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Can I Use Outdoor Gravel Or Rocks In an Aquarium? How To Use Them

Yes, You can decorate your aquarium attractively. It is called aquascaping. It is like landscaping but underwater. Rock is one of the most interesting materials for aquascaping. If the aquarium’s bottom is covered with rocks and gravel, it gives an amazing look to your tank and provides a habitat for aquatic creatures. But when decorating your tank with rocks and gravel, you should know about some important matters.

Further reading solves your issues regarding outdoor gravels and rocks in an aquarium. So let’s see Can I Use Outdoor Gravel Or Rocks In an Aquarium?

Can I Use Outdoor Gravel Or Rocks In an Aquarium How To Use Them

How do you tell if a rock is safe for an aquarium?

You can use many different types of stone and rock materials to decorate your aquarium. But not all rocks are safe and right for aquarium use. If you add rocks to your aquarium, you should ensure whether those rocks are safe or not.

The most important factor to consider when choosing a decorative rock is if the rock is inert in water in the aquarium. Some decorative rocks will release calcium into the water. This causes to increase in the hardness of the water.

It can be undesirable in planted aquariums and keeping fish species that belong to Amazonian fish Also, the rocks can release carbonates. It causes to increase in the pH level of water. In this case, you have to fight to keep the pH level neutral. But some species like African cichlid benefit from high pH levels.

How to test rocks for an aquarium?

The main danger of using your outdoor gravel and rocks in an aquarium is that they may contain calcium. It can change the pH level of the aquarium water. Before testing, you must wash the stones and rocks thoroughly to remove all contaminants.

The calcium test can be as simple as putting a few drops of vinegar on a rock or gravel. If an acidic substance is embedded on the rock and fizzes or foams on the rock, do not use this rock. The chemical reaction you see indicates that the rock contains calcium. Another method of testing rocks and gravel is to place the washed stones in a bucket with a small amount of water you used in your aquarium. Allow submerging the rocks in this water.

Firstly, check the pH level and hardness of the water, and after few days or a week, test the pH level and hardness again. If there is a significant increase, these rocks can cause problems in your aquarium.

Safe rock types for aquariums- safe aquarium rocks

• Slate and Shale

Slates can be made from volcanic activity that can vary in color or have streaks of colors (dark red, gray, and green), but most slates sold for aquariums are grey. Shale belongs to sedimentary rocks made of quartz, clay, and other minerals. Shales’ color depends on minor changes in mineral content, and colors are black, gray, yellow, and red.

• Lava Rock

When gasses in magma begin to solidify and harden, Lava rock or Volcanic rock forms, lava rocks are very porous, and you can see thousands of holes and pockets made of gas bubbles. There are several colors of Lava rocks such as black, brick red, light red, deep orange.

• Quartzite

When quarts sandstones are heated and compressed, it forms mineral quartzite: iron oxide, silica, carbonate, and clay cause to create beautiful streaking patterns. Quartzite is best for freshwater aquariums and soft water-planted tanks.

• Glass rocks

Glass pebbles or fire rock is used to decorate aquarium, which is man-made, and you can buy glass rocks in a variety of colors and sizes. This rock does not change the water chemistry.

• Rainbow rocks

Rainbow rocks are slightly colored, usually white and orange or white with red and green. This sedimentary rock is mined in Mexico. Rainbow rock is inert and does not change the pH level, carbonate hardness, and general hardness in the water. It can be seen in freshwater aquariums.

• Mountain stone

Mountain stone was famous in planted aquariums of Takashi Amano, and these rocks have a color range from dark to light gray.

• Plastic rocks

These rocks are molded from plastic and have a natural stone color. The advantage of plastic rocks is that they are very light. And also, plastic rocks can be easy to remove and clean.

• Texas holey rocks

As the name implies, this natural rock is found in Texas and has many holes. Holy Rock is made of limestone, which slowly hardens your water and raises pH levels in the water. That’s why Holy Rock is so popular among African cichlid fans.

Where to find rocks for the aquarium?

You can collect gravel and rocks in the great outdoors. Outdoor gravels and rocks can be found easily on ocean beaches, along the banks of rivers and streams, and also in dry wash beds or lakefronts. But keep in mind to avoid collect rocks and stones in underwater locations, specially protected environment. Because when removing stones can be disturbed to native habitats that wild fish and plants depend on.

How to pick rocks for an aquarium?

It can be completely destroyed if you choose the wrong kind of rocks or if they are not prepared properly. Some rocks can change the pH or hardness of the water, which is especially pronounced if there is naturally acidic water. Other rocks can be infected with bacteria and other unpleasant organisms that can be deadly to your fish.

You must never collect rocks from a highly polluted area. Another important thing is to note, that rocks collected from streams or ponds have a risk of carrying harmful bacteria and microbial organisms into your tanks. Therefore, any rock in the water should never be added directly to an aquarium.

The most important thing to keep in mind is to make sure that there is no metal in the rocks you collect.

Is aquarium gravel safe for plants?

Gravel is the substrate-of-choice it is so broadly suited to raising aquatic plants. But In most cases, gravel or sand does not have the required nutrients. This means that these types of substrates can provide nothing for plant growth.

This is why they are also called passive substrates.

Because of that, you have to choose plants that have the ability to getting most of their nutrients from the water column. Anubias, Java fern, Java moss, Vallisneria and bamboo are some of the plants that grow with gravel.

How to clean river rock for an aquarium?

• Scrubbing with a brush

This is the easiest way to clean the rock, scrub the rock using a brush under running water. Through this method, you can lose organic matter, soil, and algae.

• Soaking in pure water

Some hard minerals can be dissolved from rock by soaking rocks in distilled or reverse osmosis water. Soaking helps to remove loose minerals from cracks and pores. But this does not prevent adding hardness and raising pH level in water from rocks loaded with limestone.

• Washing rocks with boiling water

Soaking the rock in boiling water destroys the biofilm and eliminates the fear of introducing something “bad” into your tank. It will loosen dry clay and other organic matter. And also, hot water can restore the natural beauty of rock.

But some aquarists warn that when boiling rock allow damaging your rock. However, useing hot tap water instead of boiling water is good idea.

• Bleaching rock

Bleaching destroys everything and loosens organic matter. But be careful when using this. Once the soaking is complete, the remaining bleach needs to be removed. You can wash the rock with a few buckets of water or let the rocks dry in the sun.

• Acid washing

Soaking rocks in hydrochloric acid is the neutralize option,” and it can neutralize some carbonate-containing rocks. Once the acid bath is over, you have to neutralize the acid to dispose of it in an environmentally safe way.

Do we have to boil rocks for a fish tank?

Some aquarists warn that there are some dangers to boiling rocks. The safest way to boil rocks is to place them in a large container that can be completely submerged. Bring the water to a boil and keep it at a minimum temperature to maintain a steady boil. The container should also be covered, and it is best to wear full safety gear when dealing with rocks.

Check out video credits to Krish's Aquariums

How long should I boil rocks for the aquarium?

You can remove or kill any unwanted pathogens by boiling the rocks and gravel for 10-20 minutes in regular tap water. But be careful when using this method. The rocks remain hot for a very long time. Therefore, allowing them to cool before you handle them. To accomplish it, spread them on a clean surface in the sun to dry.

Can you use aquarium rocks for plants?

The fact is that some aquarium plants can grow on rocks. Mostly these are bush-like rheophyte-ish plants that have strong root systems are anchored on rocks. But In most cases, gravel or sand does not have the required nutrients. This means that these types of substrates can provide nothing for plant growth.

This is why they are also called passive substrates. Because of that, you have to choose plants that have the ability to get most of their nutrients from the water column. The use of gravel for growing plants depends on the type of plant you want to grow and its root structure. Plants with very large roots will do better in aquarium gravel than in sand or aquatic soil.

Java fern, Java moss, magenta water hedge, and dwarf hairgrass are the common aquarium plants that grow on rocks.

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.