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Does lava rock reduce nitrates in your fish tank?

Lava rock is an excellent natural décor that you can add to your aquarium as it doubles as biological filtration.

So, can you use lava rocks to reduce or completely remove nitrates in your fish tank? You can find out in this guide at Aquarium Blueprints.

Quick Summary

Lava rocks are highly porous as they contain microscopic chambers that are devoid of oxygen. As a result, nitrate-consuming bacteria will be able to colonized in these anaerobic spaces.

These rocks also provide a lot of surface area for the ammonia- and nitrite-consuming beneficial bacteria to colonized as well.

So, if you are looking to reduce your nitrates along with the ammonia and nitrites, then adding lava rocks should help improve your water quality.

What is lava rock?

Lava rock is made of molten rock that were created during volcanic eruptions. What makes this rock great for biological filtration is that it is very porous.

Can lava rock remove ammonia?

Every time you feed your fish or other aquatic pets in your aquarium, you are creating organic wastes. The uneaten food will decompose while food that do get eaten will eventually turn into excrement.

These organic wastes are turned into ammonia, a compound that is very toxic to the inhabitants in your fish tank even in small traces.

Fortunately, there is a natural bacteria that will consume ammonia. These microscopic organism grow on all surface areas in your tank, including lava rocks. Since these rocks are very porous, they can provide a lot more surface areas for this bacteria to colonized on when compared to a vast majority of other objects in your tank or filter.

Can lava rock remove nitrites?

The bacteria that consume ammonia will convert it to nitrite, which is another toxic compound for your fish and other aquatic pets.

Fortunately, there is another type of natural bacteria that will consume nitrites. This specie will also grows on all surface areas in your aquarium. Just like we stated previously, the porous structure of lava rocks should provide way more surface areas than most other objects and filter medias in your tank.

Can lava rock remove nitrates?

The bacteria that consume nitrite will convert it to nitrate. While nitrates aren’t as toxic as the other two compounds, it can be harmful at very high concentration, which is more than 40 ppm (or 20 ppm for very sensitive aquatic pet species).

While there is another natural bacteria that will consume nitrate, it is somewhat tricky to grow it in your fish tank. While the bacteria colonies that reduce ammonia and nitrites require oxygen to live, the bacteria that reduce nitrate can only live in areas that have little to zero oxygen levels.

Thankfully, lava rock contains a lot of microscopic chambers devoid of oxygen due to its porous structure. Therefore, the nitrate-consuming bacteria should be able to grow inside of these rocks.

While lava rocks should help reduce the nitrate levels in your aquarium, it most likely won’t be able to completely get rid of this compound unless you add a significant amount. As we stated above, we recommend keeping nitrates to below 40 ppm or 20 ppm.

In addition to adding more lava rocks, you can also take the following steps to help reduce nitrates:

1. Add live plants in your aquarium (we used Java Moss and Java Fern as both are easy to grow in low lighting conditions).

2. Perform regular water changes (we recommend swapping out no more than 20% of your tank water over a 24-hour period so that you won’t stress out your aquatic pets).

3. Remove any uneaten food after feeding your fish.

4. You may also want to try feeding your fish less.

What to look for when buying lava rocks for your fish tank

When buying lava rocks for your aquarium, try to look for rocks that are advertised specifically to be safe for fish tank usage. If you are looking for a specific recommendation, then we suggest getting the BCQLI Red Volcanic Rock Sphere Bio-Filter Media, which you can find on Amazon with this link.

Generic lava rocks should work as well. You just have to make sure that there aren’t any additives included. If you are looking for a specific recommendation when it comes to generic lava rocks, then we suggest picking up the American Fire Glass Medium Lava Rocks, which can be found on Amazon via this link.