Using rocks out of your garden is a cheaper option; however, it's risky since there's a lot that could go wrong. The stones can affect the water quality or contaminate the tank.
But on the other hand, using the right tests, you may be able to eliminate the bad rocks.
So how do you know which rocks are good and which ones to avoid? Should you pick rocks instead of buying? Let's talk more about your aquarium rocks.
Rocks affect the water's pH, so it's best to avoid those that are high in calcium for freshwater tanks. They harden the water and make it alkaline, for example, stones like marble and limestone.
On the other hand, saltwater tanks need a higher PH. Therefore, they need these alkaline high, calcium rocks.
You can choose rocks like Ohio dragon stone, black lava rocks, or slate rock for aquariums. These won't affect the pH of the water.
In most cases, granite is a universal rock that you can use in both freshwater and saltwater aquariums.
These rocks are readily available; you can buy them from most places.
Here are some rocks that you should avoid:
The best way to determine if rocks are safe is to test them for pH. The first step is to thoroughly wash the rocks to eliminate any mud and grit on the surface.
Just be careful not to clean with soap or detergent since this may alter the pH. Once the rock is clean, there's are a few tests you can do.
The first test is as simple as putting a few drops of vinegar on the rock.
If the vinegar fizzes, it means the stone has too much calcium, and you should avoid it.
The test sounds simple enough, but it's based on actual chemistry.
The vinegar is an acid and will react with the alkaline calcium; that's why it bubbles.
Any acid will do for this test; some recommend using a stronger acid like hydrochloric acid - but what are the odds that you just have some hydrochloric acid lying around?
The second involves putting the clean rocks in the water, letting them sit for a while, and then testing the water's pH.
After about a week, retest the pH. If the water's pH goes any higher within the week, the rocks are not suitable for your tank.
All the pH stuff may be too technical, but don't let it confuse you; remember the key takeaways:
Picking rocks in your garden should be fine as long as you follow some guidelines, including;
Find rocks in habitats that fish naturally thrive, such as beaches, along streams, and in dry wash beds.
Just be careful not to disturb habitats that plants and aquatic animals depend on.
It's also a good idea not to pick the rocks directly from the water to avoid carrying any bacteria with them.
Considering using outdoor stones? That's understandable, especially If you're working on a tight budget, with all the other equipment so expensive.
But you have to take great pains to make them safe for the aquarium.
There are two common methods for making rocks safe.
Place the rocks in a large covered pot and bring up to a stable boil. Make sure the stones are fully submerged and boil for 30 minutes.
Then allow it to cool off completely before using it in the aquarium. This helps to kill any contaminants on the rock.
You need to be very careful if you decide to do this. Don't boil the rocks for too long since they might explode.
It's also a good idea to wear protective clothing. And be warned that rocks get extremely hot when boiled and take a long time to cool, so be cautious not to burn yourself.
You can also submerge the rocks in a dilute bleach solution (10:1). Let them sit for a day or two. Then take them out and wash thoroughly.
Allow the rocks to stand in clean water for another day or two, and then rewash them. You can repeat this cleaning process for a few days (about a week).
You may have noticed that these methods do nothing about the calcium content of the rock.
So in effect, if a stone has a high calcium content, there's nothing you can do to make it safe for the aquarium.
Using outdoor rocks is risky but not entirely off-limits. If you select your rocks from the right places, check their pH and purify them to eliminate bacteria, they should be perfectly safe. However, it's always safer to buy aquarium-ready rocks from the store.