12/26/2007, 06:15 PM
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RC Mod
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Join Date: Mar 2002
Location: Foster City, CA, USA
Posts: 35,743
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Silicate is used by many sponges and snails:
http://advancedaquarist.com/issues/jan2003/feature.htm
Growing diatoms can also be a useful exercise.
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Jonathan Bertoni
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