New Rocks For New Aquarium- Are They Safe?

[don_kihotis]

Hi guys, yesterday i visited a local pet shop and bought these 2 big pieces of rock for my new aquarium but wanted to make sure that they are safe thus i am posting here for your reviews.
 
I have had lava rocks in the past without probs and some other kind of stones but i have never seen this type before.
 
What do you think? 
 
 

By the way i am not sure if this is the correct section of the forum for posting, so if not mods please move this thread to the right place.
Cheers

 

[techen]

Do the vinegar test.
 
Pour a small about of vinegar onto the rock, If it starts to hiss it's unsafe. If it does not, you're good to go.

 

[Byron]

That looks to me like basalt, I have some of this in one tank.  But it could also be calcareous, like limestone.  Techen's acid test will tell you.  Fizzing with an acid like vinegar means calcareous, and this will thus dissolve calcium and hard minerals into the water, increasing GH and pH, depending.
 
Byron.

 

[don_kihotis]

Hi guys, thanks for the replies.
I did the vinegar test and zero reaction. I was waiting a few minutes but still nothing. I guess i am proceeding with the set up now
Thanks again

 

[DrRob]

Word of warning, my wife is both a geologist and a vinegar aficionado. She tends to laugh when people mention using vinegar to test rocks, not because it doesn't work in principle, but because it needs a good quality, strong vinegar, which isn't the easiest thing to buy sometimes as what we have in our pantry cupboards is often so weak that the fizz would be very slow and difficult to spot. You also, ideally, need to clean (this appears to involve scraping with a knife) a piece of rock to test properly. She has a small bottle of acid for testing rocks, but has been known to resort to limescale cleaner to test if she hasn't get any of her normal acid to hand.
 
As for being bad, it does depend a bit on the tank. Rocks that will dissolve can be a problem as they may reveal concealed metal deposits as they slowly break down over time, but in a hard water tank can be a boon as they help to buffer the water, although the surface area of the substrate tends to be a better method of doing this.

Oh, and she reckons the rock looks metamorphosed. Falcite was one of her answers, which could be problematical but should fizz.

 

[Byron]

On another forum I used to recommend a stronger acid and got voted down, so I acquiesced, but I do agree that vinegar, which we do put on food we eat, is not the strongest of acids by any means.  I believe the Regent #2 in the API nitrate test is a strongish acid, and that is often recommended for this test.
 
Byron.

 

[DrRob]

Well I'm with you, if you have access to a stronger acid it gives a much clearer result.

 

[don_kihotis]

Thanks for the replies.
I have used the white vinegar which is stronger than the red one but still not as strong as an acid you can get from the pharmacy store.
Maybe i should try with the bottle #2 from the nitrate test. That one is quite strong and burns your skin even through clothes.

 

[Byron]

Thanks for the replies.
I have used the white vinegar which is stronger than the red one but still not as strong as an acid you can get from the pharmacy store.
Maybe i should try with the bottle #2 from the nitrate test. That one is quite strong and burns your skin even through clothes.

This would be better, all it takes is one or two drops.

 

[don_kihotis]

Hi guys, i couldn't find API NO3 kit so i got a Sera instead. The problem is that this test kit has 3 liquid solutions and not 2. So does anyone know which one is the strong acid that i can use to test my rocks? I checked the instructions leaflet but it has no chemical description of the solutions. Then i did a google search but still nothing.
Here is link of the product: https/www.sera.de/en/products/in_category/einzeltests-5589/product/sera-nitrate-test.html

 

[don_kihotis]

Well since i didn't know which liquid in the test kit was the strong acid, i tried them all. I scratched one of the rocks with a knife and a small piece fell off. I droped some of each liquid and still no reaction. So i decided to place them in the tank. After a while i noticed that both rocks have gas inside them since there are tiny bubbles coming off in a row like a chain. The bubbles are slightly larger than those of the CO2. Is this conventional or it basically means that they are dangerous?

 

[Byron]

Well since i didn't know which liquid in the test kit was the strong acid, i tried them all. I scratched one of the rocks with a knife and a small piece fell off. I droped some of each liquid and still no reaction. So i decided to place them in the tank. After a while i noticed that both rocks have gas inside them since there are tiny bubbles coming off in a row like a chain. The bubbles are slightly larger than those of the CO2. Is this conventional or it basically means that they are dangerous?

That is air from inside the rock, likely harmless in itself.

 

[don_kihotis]

Cool Byron, i am so glad to hear this

 

[don_kihotis]

Just adding some photos of the rocks in the tank.