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Is black axe stone "unsafe"?


CT_
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I picked up something that was called "black axe stone" for a (cherry) shrimp tank I'm setting up and when i brought it home I poured a little acid over it and it fizzed quite a bit.  I'm told this is the test for "unsafe" rock but I'm not totally sure why.  If I'm going to be using crushed coral anyway does this rock really pose a risk?

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On 2/11/2022 at 11:12 PM, CT_ said:

I picked up something that was called "black axe stone" for a (cherry) shrimp tank I'm setting up and when i brought it home I poured a little acid over it and it fizzed quite a bit.  I'm told this is the test for "unsafe" rock but I'm not totally sure why.  If I'm going to be using crushed coral anyway does this rock really pose a risk?

I strongly recommend reading the AquariumScience blog.

We are told that rock that reacts (bubbles) in response to acid (frequently vinegar) is unsafe.

Why?

First, we need to understand why the rock bubbles...which is the same reason baking soda bubbles: add an acid to an alkaline substance and the chemical reaction yields carbon dioxide, CO2.

We know our plants need CO2, so why is this rock supposedly unsafe?

Did you know that if you pour vinegar on your crushed coral, it will bubble too?

So, why have we been told not to use rock that is calcium carbonate rich in our tanks, while being told to buy crushed coral to stabilize our tank parameters?

Read the Aquarium Science dot org (or is it dot com🤔) and find out which 'wives tales' are interfering with enjoying your tanks.

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^ Basically what Torrey said, but I’ll add some caveats. I too have read that blog and what it doesn’t go into is that the rock that fizzes isn’t necessarily calcium carbonate. It could be magnesium carbonate, or something else entirely. It’s highly, highly unlikely it will be anything that directly harms your aquarium, but if you have a planted tank or want to keep things acidic, it may make your water too basic and change the chemistry in an unhelpful way.

It’s not dangerous to fish or shrimp, but you’ll have to watch your pH and hardness to make sure it’s not swinging either of those parameters in a direction you don’t want.

If you want to test it, put the stone in a large jar of water and let it sit for a week. Get a second jar and fill it with water (but no stone) and let it sit for a week as well. Then compare the water chemistry and see what the rock did, if anything.

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Thanks guys.  The above pretty much echos my exact thought process.  And I'm probably not missing something.  Common wisdom is at least worth double checking if you're going against it :)

 

  It would be nice to know the geological name of this stone so I could know what minerals I should "worry" about but I can't think of anything common that's scary.

On 2/12/2022 at 4:38 AM, Guppysnail said:

What type of acid. I’ve always used vinegar (curiosity for me). I have seen black axe stone sold for aquariums but have never used it so do not know what affects it produces in the water column. 

I used sulfuric acid.

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On 2/12/2022 at 1:02 PM, CT_ said:

Thanks guys.  The above pretty much echos my exact thought process.  And I'm probably not missing something.  Common wisdom is at least worth double checking if you're going against it 🙂

 

  It would be nice to know the geological name of this stone so I could know what minerals I should "worry" about but I can't think of anything common that's scary.

I used sulfuric acid.

Oh, you played with the fun stuff🤩

I'm looking for black axe stone, to get an idea... do you have a link?

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Yeah I should say my acid was sold as API ph down so it's actually easy to find.

 

Black axe not that commonly mentioned online.  what I got looks like this (the black ones not the brown pebbles). 

https://s.alicdn.com/@sc04/kf/H1e28613d9ce54f3081ed510af0031010a.jpg_720x720q50.jpg

I should have been suspicious of the white streaks but the guy at the store said it won't change my water so I figured the white was quarts

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