# Floating lava rocks



## methodica (May 15, 2007)

I redid my tank tonight and came up with a very odd problem. I tried using lava rocks and some of my larger ones are floating. Are these rocks junk now or will they enventually sink?


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## Zapins (Jul 28, 2004)

Floating pumice rafts have been known to float for months in the sea, they float for such a long time that barnacles and other marine life can attach and build a community.

Your lava rocks are formed when a gassy lava rock cools quickly trapping the gas inside the rock as bubbles. This makes the entire rock very light and buoyant since its mostly made of gas with small amounts of glassy rock around the bubbles.

I think it might take a very long time for the lava rocks to sink. You might want to try attaching weights to the bottoms of them. You can do this easily by drilling a few holes into the lava rocks and threading through string, then you can attach weights to the string. Eventually the rocks might become waterlogged but I think it might take several weeks.


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## spypet (Jul 27, 2007)

drilling a hole through the rock using a small 1/8" masonry bit should expose more air trapped inside the rock and help to water log it. make sure to rinse the rock dust off from drilling before submerging the rock back into your tank.


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