Is Lava Rock pH Neutral? Read This First!

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When adding anything new to your setup, it’s always a concern whether it will affect the pH level of the water in your aquarium or other aquatic setting. Keeping the proper pH level is essential for maintaining a healthy “mini-ecosystem,” so you may be wondering if adding something like lava rock will affect these levels or cause any other types of changes.

Lava rock is often a pH neutral substrate. However, it depends on the type of lava rock used and where it comes from. Certain types can be acidic while other types have varying levels of porosity, both of which can affect pH balance.

Whether you want to use lava rock in an aquarium, a garden setting, or with a hydroponics system, it’s a very ideal substrate to include. However, you need to ensure you get the right kind for your intended purpose. This means that you’ll need to look for a product that’s advertised as being pH neutral.

How is Lava Rock pH Neutral?

Moreso than other types of rock, lava rock is natural, pH neutral, and very light. It’s porous, readily available, and easy to acquire. For aquariums, it provides the best possible environment for fish due to the beneficial denitrifying bacteria it contains. This improves the water quality by helping to remove harmful nitrates.

However, there are certain types of lava rock that can be acidic. Due to the fact that it’s molten rock produced as a direct result of a volcano, there are a host of substances and materials that can comprise lava rock of any type. Therefore, you’ll need to be sure that you use the porous type of lava rock and not the glass-like lava rock known as “obsidian.” The pores in the lava rock we’re discussing today are what help to keep everything neutral and alkaline while not adding any acidity.

What is pH Neutral Lava Rock Used For?

Such a neutral and beneficial substrate is invaluable for soils that have high acidity levels and fish tanks that need help filtering out nitrates. When used in these situations, you’ll want to ensure that there’s no tufa, limestone, or coral that composes any part of the lava rocks. The good news is that manufacturers will generally indicate on their packaging how their particular version of lava rock should affect pH balance.

Where Does Lava Rock Come From?

Lava rock used for aquariums or gardening comes from natural deposits in the earth from a long-passed volcano. Lava rock from a fresh volcanic eruption will not be suitable for such purposes. This is because the elements and the seasons need to “work on it” a bit before it can be naturally processed enough to be appropriate for horticulture or aquarium use.

Once mined, it then undergoes the process of being broken down into smaller pieces. The horticultural use lava rocks will have irregularly sized pieces, and the lava rocks for aquatic purposes will be more pebble-like. They can also come in a variety of colors such as gray, black, orange, red, or brown.

What are the Pros and Cons of Using Lava Rock?

As with everything, there are also pros and cons when it comes to using lava rock. On the positive end, it’s lighter than sand or gravel, and this makes it infinitely easier to work with—however, it’s still heavy enough to stay weighted down.

Also, lava rock retains water well because of all of the pores. These pores can help the roots of plants to grow for gardening and hydroponics. Regarding aquariums, they additionally help to purify a tank of its nitrates, give nano fish a place to hide, and provide a base for plants to attach.

As for cons, one of the main issues worth noting is during use in an aquarium. Be sure to not include any pieces with sharp edges that may be capable of harming your fish or any other living creatures inside of your tank. Lava rock’s otherwise beneficial porosity can also cause it to retain more debris and fish waste, which will contribute to more cleaning and potentially more issues.

When used in a garden setting, lava rock is also not a substance that will decay. This may seem ideal (and may still be the best option depending upon specific uses), but this additionally means it will not break down and add nutrients to the soil at any point like most other substrates.

Other Things to Note

Although it is a bit dusty at first, that will clear once you rinse off the lava rock you intend to use. So, regardless of your purpose for using it, you should be sure to first rinse it off. This also helps ensure the lava rock’s neutrality.

The problem with using lava rock for gardening is the uneven and irregular surface it creates. There are smaller and more rounded lava rocks for horticulture, but these also come at a higher cost because of the tumbling processes used.

However, lava rock pebbles for an aquarium should always be smooth and advertised to be safe enough for fish.

Do You Still Have to Check pH Levels When Using Lava Rocks?

After adding the lava rock to your tank or soil, check the pH levels on a regular basis to ensure nothing is happening with them and they are remaining stable. Any significant changes of the pH levels will need immediate correction. That is the only way to save your precious plants and/or fish.

Where Can You Find Lava Rocks? What Do You Look for?

The best place to find lava rock is at a local hardware store, home improvement center, hydroponics supplier, aquarium shop, gardening center, a substrate mining company, or through a vast host of sources online. Keep in mind, though, it can get a little pricey. Due to high costs, it’s best to shop around at a variety of places and do a little comparison research before purchasing.

Sometimes, it will be cheaper on Amazon; other times, you’ll get a better deal from the hardware store down the street. But, whatever you do, do not use lava rock intended for horticulture in an aquarium nor vice versa. The results will be devastating, and it’s best not to risk it.

Another thing you’ll want to keep in mind when hunting around for pH neutral lava rock is the geographic location of from where it came. The best area for lava rock that is most suitable for fish and plants is Hawaii. The lava rock from these islands has the best components to provide nutrients into the soil or simultaneously be a safe substrate for a tank.