# Are these rocks safe?



## Jaimefout (Nov 13, 2017)

I'm in the process of setting up a new 55 gallon African cichlid tank. I bought some rocks from a landscaping supply store and have been cleaning and recleaning them over the past few weeks while cycling my tank. I've noticed some whitish-grey looking spots on several of them and was wondering if anyone could look at the attached pictures and see if you know what this is and if it's unsafe? The rocks are supposed to be Tennessee Fieldstone.

https://photos.app.goo.gl/AyVVZn3s85giQHji1


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## MJCanAm (Jan 1, 2018)

I believe there's a test where you pour vinegar on the rocks and if it fizzes or bubbles it's unsafe and if it doesn't it's safe. I remember seeing it somewhere on google.


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## DutchAJ (Dec 24, 2016)

MJCanAm said:


> I believe there's a test where you pour vinegar on the rocks and if it fizzes or bubbles it's unsafe and if it doesn't it's safe. I remember seeing it somewhere on google.


I've seen this test mentioned before, unfortunately it will not indicate if a rock is aquarium safe. Limestone (calcium carbonate) will fizz in vinegar and is perfectly safe on its own. It's the trace minerals to worry about.

I cannot tell what the white/gray crystals are from the pics.


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## DJRansome (Oct 29, 2005)

I would put them in my tank...but IDK what they are either. I did not have the impression of crystals (vision issue?), but what came to mind was after cleaning algae some remains in the tiny pits of the rock and then looks white when submerged for a while.


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## DutchAJ (Dec 24, 2016)

DJRansome said:


> I would put them in my tank...but IDK what they are either. I did not have the impression of crystals (vision issue?), but what came to mind was after cleaning algae some remains in the tiny pits of the rock and then looks white when submerged for a while.


I also would put them in my tank, we just can't guarantee anything from those pictures. A close up (as close as you can get in focus and dry) may give a more definitive rock id though


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