# Natural iron 'filings' in our sandy soil near the river and in the river



## Luminescent (Aug 14, 2013)

Natural iron 'filings' in our sandy soil near the river and in the river.

See the bottom 2 pics:


http://imgur.com/6ac9Z


I actually discovered that by accident when drying some river sand to add to the 40 Gal substrate when a roll of magnets rolled over near it.

Tom Barr says they provide a natural source of iron.

There are also fine mica chips and a few flakes of gold in the sand.

Thoughts?


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## Phil Edwards (Jan 22, 2004)

If you're up in the Sierras your stream sediment will be composed of volcanic minerals, many of which contain iron. It's likely that it's a remainder from rock containing more soluble minerals. That's also probably where your gold's coming from. It's often found in conjunction with ferromagnesian igneous deposits where hot water dissolved the gold as it worked its way up through the crust then it precipitated out as the water cooled. I'd be careful adding too much of the sediment to your tank as it may cause issues with excessive iron. Best run a magnet through it, or over a thin layer, to get the majority of the iron out if you can.


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## Luminescent (Aug 14, 2013)

Thank you. 

I basically just 'dusted' the base of the tank with a thin layer of the sandy soil. I know I can grow any land based plant in it- like gangbusters.


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## Phil Edwards (Jan 22, 2004)

Sounds like you're good to go then.  Volcanic sediment/soil is rich, that's for sure.


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## Luminescent (Aug 14, 2013)

I have put a layer in all my tanks now. Haven't added any Iron supplements and getting good reds so far.


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