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Is an acid test REALLY enough?

Clint

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Should I care at all about any elements rocks may release as long as the rocks I use pass the acid test? I'm not really worried about Pinguicula or Nepenthes, but I'd also like to grow Utricularia and Drosera in a terrarium. I'd really like to use rocks that look calcerous but aren't. Something that looks like lace rock (that would be perfect, but changes PH :( ) but won't harm the plants. The best thing I can think of is lava, but the elements it may release have me worried. I've always been really hesitant to use lava even though many do. I'm afraid It'll just be my luck that I get some from a crappy volcano :(

I could always use pumice and could carve it into what looks like lace rock, but pumice is an ugly color. Can you safely dye/stain rock? Not like a tannin stain, but like a real stain from a dye. This is actually the rock I wanted to use until I saw the disclaimer that it may raise PH :( http://www.adana-usa.com/index.php?...s_id=4&zenid=8a2d9ff936f59d257ecd135df2c3540b
 
im not sure what your saying here, you want to build a terrarium?

i wouldnt use lava rock to risky
 
Yeah, but this applies to anyone wanting to use lava.

Lava rock is a common ingredient.
 
Hi there,

Although I am relatively new to growing cp's, I did do my undergraduate in Geoscience and could at least give you an opinion on this.

I can tell you that some lava rocks, like rhyolite, should be 100% safe. It is a silica rich, and should not be unlike using a silica sand.

I would be more concerned about some other types, I visited some places in New Zealand where the rocks were high in Iron, Magnesium, and some other metals and actually stunted/killed plants. That stuff is rare, but a lot of the Mafic lava rocks (gabbro, basalt) are along those lines: abundant metals and could potentially cause problems.

I guess I would ask if you had a particular type in mind, and if not, could you describe color/texture? as that could help determine what type you were looking at.
 
I think the best thing to look for would be chert, the wikipedia page on it has a pretty good image to give you an idea. Colors are highly variable, but in all forms it is just microcrystalline quartz such that it looks not unlike a typical stone despite being near pure SiO2.

The unfortunate part is that few places will be actually selling 'chert'. they could call it any number of things. You should be able to find a big bag of it at your typical big box garden/hardware place, trick is identifying it.

The stuff is hard, a metal blade should not scratch it, and it tends to be somewhat smooth on faces and sharp where broken. Having done a thousand hardness tests though, it's not a surefire indicator.

Without a whole lecture on the stuff, it might be hard to pin it down. But I can bet that it will be cheaper than the stuff you were looking at, and might be listed as "Meramec" or "River Pebbles" . Could also be called 'jasper'.

Let me know if that helps at all.
 
I looked it up, and I'm getting smooth pics that look like flint, and also rough pics like this:
http://www.cuesta.org/deptinfo/geology/Images/chert2.jpg

I'm really just going for something that resembles Live Rock (well... dead live rock :p ) without leeching anything. Using actual dead live rock would be suicide, no matter how fantastic it would look for the first few days :p
 
i dunno but I hope your succesful in your jouney if your planning on setting up some rocks in your terrarium ( thats what I assume the plan is ) if you can find a good rock it'd be pretty cool looking. so yeah just voicing my approval and anticipation..
 
Well, flint/chert/jasper are all the same thing to some extent, depends on quality and so on. The real smooth flint type stuff you speak of is probably not the sort of thing you would find at a hardware place, it would most likely be on the rough side of things. I may go take a look for myself in the next week or two when I am looking for other things.

It is my guess that you might be satisfied with the sort of stuff that is considered gravel quality, but until we see, its up in the air.

This stuff would be about as leach proof as I could think of in terms of 'live' rock as you say.

As an alternative, some Granite gravel would be pretty good as well, it would be unlikely to do much and is made mostly of silica rich minerals. would be more plain for texture though. Slate gravel is kind of a crap shoot.

I did take a look at those stones in the aquarium shop, and I would be a bit hesitant, they use common names so its tough to tell what they are from the images. They even mention they can leech.

In general, the larger the particle or stone, the less leeching you can get. The ones I have mentioned are totally safe, but even a lot of the others would probably be fine. The problem with the carbonate ones is that the acid in the bog setups reacts with them to a greater extent. So, if you can track one of those I mentioned down, then your safe for sure, but otherwise I would not go crazy over it. I would still be careful about dark colored lava rocks though, and think that they best be avoided.
 
  • #10
Hah! Look what I found. A french company called Aquaroche makes ceramic faux live rock. One version if for marine water, but there's a freshwater version that's neutral. Made from baked clay, and I must say that it really looks indistinguishable from dead live rock. They can even do custom stuff.

This is perfect. Check it.
http://www.aziendanaturaviva.com/images/720X540cae.jpg

http://www.aquaroche.fr/gb/
 
  • #11
Very nice, that solves the problem about as well as I could imagine without having to identify rocks either.
 
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