Mexican driftwood rock & Peridot Rock?

Biollante

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Vinegar

d0lph1n;53907 said:
Do you know if it's safe to use these rocks in a freshwater aquarium with Tetras & Amazon plants, ph 6.6-6.8:
1. Mexican Driftwood Rock
2. Peridot Rock

What is the best method to test a rock if it's safe or not for fish & plants?

Hi,

I would not. :gw

Vinegar. :cool:

Biollante
 

d0lph1n

Junior Poster
Jul 19, 2010
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Thanks for all replies.

I've modified my first post with links. My peridot rock looks similar. The vinegar had no reaction with this rock but it had some with half of the mexican driftwood rocks.
 

Biollante

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Olvine Solid Solution

Hi,

I did a little more research; likely, my arrogance prevented me from doing so earlier. :eek:

I still would not use either in an aquarium. I am sure the Peridot rock would tempt me. :eek:

The Mexican Driftwood Rock is a definite no as your vinegar experiment demonstrated.

The Peridot is a lot closer call; it is Forsterite, Mg2SiO4 an olivine solid solution, it looks beautiful. :)

If you choose to use it, keep a close eye on the water quality and the rock. I would advise waiting until the aquarium is well cycled, critters happy, and plants growing and stable before adding the Peridot rock. :gw

Biollante
 

d0lph1n

Junior Poster
Jul 19, 2010
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Thanks for your advice.
So, I'll put this rock in a bucket with some water from my tank and check if the ph changes. This type of peridot seems a perfect match for dark substrate & green plants but it might become too fancy or cheap looking if it's not used with moderation.

My tank is 6-8mo old and I'd like to redo the substrate and rearrange everything, that's why I'm looking for rocks & driftwoods. I have no idea yet...and I got the mexican driftwood rocks looking for driftwood in a place that sells rocks :)

Initially I was looking for petrified wood, but the seller advised agains it for aquarium use saying that the ones they have is too ferrous. They have few types of Peridot, the porous/volcanic type (showed in the link) got my attention. When I paid for the mexican driftwood he gave me a peridot rock for free.
 

d0lph1n

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Jul 19, 2010
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This guy is also suggesting HCL for testing rocks:
"...a more complete test is to drop dilute HCL (can find at hardware stores) and see if it fizzes"

or this suggestion:
"if you have a nitrate test kit, you may also already have a better test than vinegar for lime content in rocks. My Aquarium Pharmaceuticals Nitrate Test contains two bottles of prepared solutions. Solution #1, labelled "Caution: contains hydrochloric acid," comes in a handy squeeze dropper bottle. If a drop or two on a candidate rock fizzes, or even bubbles, that rock would raise the pH in the aquarium"
 
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Biollante

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How Conclusive Do You Require?

Hi,

It is a more conclusive test. :)

I think for most purposes vinegar is sufficient. :cool:

Biollante
 

d0lph1n

Junior Poster
Jul 19, 2010
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Mexican driftwood: it reacted violently with the HCL (muriatic acid from Home Depot, pool supplies), even the rocks that didn't have any visible reaction with vinegar
Peridot: Biollante, you are right. It's a closer call, "Forsterite, Mg2SiO4 an olivine solid solution" had no reaction with Muriatic Acid. I feel confident about it. I'll do the ph test with a bucket of water. Thanks again for all your help.
 
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Biollante

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Hi,

I think I would be tempted to try that as well, seems like a beautiful point of interest for any display. :cool:

I look forward to report of your progress! :gw

Biollante