Rocks for the Aquarium

Our beach outing earlier was tiring, but fun. We went to a part of Ternate, Cavite. Like what I usually do when I go to new places, I try to look for things that I can use for aquarium design.

More often than not, I tend to look for pretty rocks because they really add a lot to the beauty of an aquarium.

It’s really a simple layout, but doesn’t it look pretty? One more thing – it’s one item that you’d think is cheap – but no! They’re really expensive because they’re sold on a per kilo basis. The bigger they are, the more costly they get. For example, if you fancy a 5 kilo rock that’s sold for P50, that’s a whopping P250 already! If you just picked them, of course, it’ll cost less because it’ll be free! However, not all rocks can be used safely in an aquarium. They need to pass the acid test to ensure that they’re safe for fish.

So what’s the acid test? It’ll test if a rock will slowly dissolve in water. If the rock could dissolve over time, they can release chemicals that might poison the fish. It’s a good thing, though, that the acid test is easy to perform. Here are the steps:

1. Pick a part of the rock that you can scratch.
2. Drop some acid on the scratched section.
3. Check if the rock will fizzle and react with the acid.

When you scratch the rock, pick a part that will not be visible when you use it in a layout. Use something hard like a pickaxe to scratch it. For the acid, regular vinegar will do, but the fizzling is more dramatic if a stronger one is used. Some common acids in the house are actually cleaners like muriatic acid or hydrochloric acid. You could use those.

If the rock fizzles, it means that the rock fails the acid test and you can’t use it. Over time, it will dissolve in the water, especially if you know that your water is especially acidic. If it doesn’t fizz and react wit the acid, it’s alright to continue cleaning the rock and use it as part of an aquarium design.

I did test some of the rocks I brought home earlier. Here’s a picture of one of the rocks that passed the test:

It didn’t fizzle, so it’s ok. Now, here’s a video of a rock that failed the test:

Noticeably, the part where I dropped the hydrochloric acid fizzed instantly. That’s why it failed the test.

Out of the sack full of rocks that I brought home, only three passed the test. It’s sad – not to mention backbreaking – but it’s alright because, at least, I now know which ones I can use in my aquarium without harming my fish. I’ll just have to wash the rocks that passed the test and disinfect them so that I can have them ready for the new aquarium that I’m planning to set up.