Rocks ? Are They Ok ?

[Nick Sw]

Hi I bought these Rocks yesterday for my new tank, they are from B & Q, I`ve heard the River Cobbles are ok but after another look these maybe slightly different some of them were definately labelled River Cobbles but some were from another basket (described as Long-something ??) , after cleaning them up there are lines of sediment in the rocks and small metallic particles can be seen under the light.

Not a Great Picture I know but do you think will be ok ?

Any help appreciated
Nick

Rocks Pic Here

 

[mamafish68]

Look for any rust to develope, if it does, toss it in the garden.

you mentioned metalic bits... metals & tanks=not good

I've seen publication of a vinegar test that can be done if it bubbles toss the rock

 

[Ginge]

Just looks like river rock to me and thats perfectly safe.

 

[chishnfips]

I was given a good idea to test a rock, if you have a strong magnet you can pass it over the rock and if you feel it move slightly then you know there is metal in it.

I tried it with a small magnet in between my fingers and every time I passed some metal on the rock you see the magnet sway.

just a thought....

 

[Nick Sw]

Thanks for the replys.

I tried the vinegar and I didn`t see any reaction at all, there is some rust but I`m certain that is just staining from where the stones have been in contact with the metal cages they are transported in.

I did say metallic maybe I meant shiny or particles that glisten I`ll have a closer look at those and just check and I`ll try the magnet .

Thanks again Nick

 

[bobf]

Thanks for the replys.

I tried the vinegar and I didn`t see any reaction at all, there is some rust but I`m certain that is just staining from where the stones have been in contact with the metal cages they are transported in.

I did say metallic maybe I meant shiny or particles that glisten I`ll have a closer look at those and just check and I`ll try the magnet .

Thanks again Nick

If I remember my geology correctly the "shiny or particles that glisten" will be feldspar or quartzite crystals and will have been stable for a couple of million years or so, so I don't suspect that they will hurt your fishes.

If it is a goldy/silver mettalic colour then it's probably pyrites (copper or iron pyrites - fool's gold!) and again very unlikely to be unstable in any way. Magnetic rock usually indicates haematite (sp?) - kind of iron ore, but the rock would be reddish colour anyway.

Reactions to vinegar would indicate the presence of carbonate minerals like calcite or dolomite - limestone is the commonest example. For a Mbuna tank this would not be a problem anyway as it would raise and buffer the ph. Limestone is a sedementary rock and is 'softer' than the rocks you have - it would have broken rather than being rounded off like a pebble - you would be able to easily break it with a point like a screwdriver.

What you have are metamorphic rocks - sedementary rock changed by heat or pressure, hence the crystals being formed. Consequently they are much harder and more dense than sedimentary rock. These have then been eroded either in moving water like a river or the sea or often (surprisingly) pushed along at the foot of a glacier (back in the ice age/s). They then have another name which escapes me?

If there are any more recent geology grads here feel free to put me right as this is from memory from abouit 25 years ago!

 

[Marcos]

So are rocks from a fresh water river usually safe? (I suppose it would make sense) The vinegar and magnet test could be carried out. I suppose a compass could be used?

 

[denis coghlan]

Bodf, what you have written sounds right to me. I'm sorry Nick that in the pm's between you and myself I called them sedimentary rocks, I forgot about the changing into the metamorphic part afterwards due to pressure and all that jazz.

Nick, when I said more opinions are better, looks like I was right.

I'm now off to brush up on my rocks and geology.

tanks

 

[mamafish68]

found some extra info:

Testing Rocks
To test the composition of your rock, put a few drops of hydrochloric or muriatic acid on it. If it foams, it's calcareous, and will affect the hardness and pH of the water. Limestone is probably the most frequently encountered calcareous rock, followed closely by marble.

Another means of testing the effect an unknown rock will have on your aquarium is to fill a bucket with water from the water source you plan to use.

Then test and record the pH, hardness, nitrates, and phosphates. Place the rock in the bucket, let it soak for a week and test the water again. If there are no changes, the rocks are not likely to cause a problem. If the parameters change considerably, I'd advise against using the rock in question.

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HOLEY COW WHAT IS ALL ^^^^^THAT STUFF? LOL

 

[Nick Sw]

Bobf thankyou very much for taking the time to post that information that does make sense and I`m sure is correct.
I`ll try the soak test as suggested by mamafish just to make certain.
Thanks Nick

 

[Cheffi]

Those rocks are just what I'm looking for and from b and q you say? Can I be rude and ask how much you paid? Thanks

 

[Ginge]

Bet it was alot. You can find ones like em in streams and lakes.

 

[Nick Sw]

They are from B & Q some are Medium River Cobbles which were a £1.00 on offer reduced from £2.28 (Huddersfield Branch) the others were something else I think but I got charged the same anyway. I bought 12 - £12.00.
I was fairly pleased with the price although Stone Merchants are cheaper I found one locally that you could collect your own and fill a 25K bag for £5.00 but in between going back I spotted these.

P.S. I tried the magnet absolutely nothing.

 

[bobf]

They are from B & Q some are Medium River Cobbles which were a £1.00 on offer reduced from £2.28 (Huddersfield Branch) the others were something else I think but I got charged the same anyway. I bought 12 - £12.00.
I was fairly pleased with the price although Stone Merchants are cheaper I found one locally that you could collect your own and fill a 25K bag for £5.00 but in between going back I spotted these.

P.S. I tried the magnet absolutely nothing.

Garden centres might be another option too!

Do check out tufa rock if you can find it too - much lighter (usually cheaper too) and can stacked up high in the tank without adding anything like the same weight big pebbles do. Consequently much more useable cave space an hidy holes. Plus it will help buffer the ph as it contains calcite.

I think it looks more natural too, but personal choice prevails, obviously!

 

[chishnfips]

aw well it was worth a shot, you wont feel a great lot of movement in the magnet its very slight.