# The use of pumice...



## MiamiAG (Jan 13, 2004)

Pumice is a light, porous volcanic rock that forms during explosive eruptions. It resembles a sponge because it consists of a network of gas bubbles frozen amidst fragile volcanic glass and minerals.

Pumice comes in various grades. I use the smallest grade of pumice as part of my semi-organic substrate. It provides an excellent environment for the colonization of microorganism and the recylcing of nutrients in the substrate solution.


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## Raul-7 (Feb 4, 2004)

Where do you get it from? Any online source?


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## MiamiAG (Jan 13, 2004)

Not that I know of. You can get it at your local orchid supply house.


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## JLudwig (Feb 16, 2004)

Art_Giacosa said:


> Not that I know of. You can get it at your local orchid supply house.


This seems to be one of Amano's "secret ingredients". The more and more I think about everything that has been said about fertile substrates, the more one theme seems to be emerging:

Just like an aerobic biofilter, planted tanks need a healthy colony of anaeorbic nitrate/iron reducing bacteria.

The little things you do to help these guys along can help a lot in the long run. You basically need the following things - a deep substrate (3"+)of small particile size. If the substrate is not deep enough or fine enough oxygen can diffuse into this layer. You also need surface area for these bacteria to grow on (pumice is good, so would be lava rock, activated carbon, be creative!) and some organic matter to decompose and force the substrate into an anaerobic state (mulm, which also has bacteria is good, peat, earthworm castings, etc... just don't overdo it...). You also need a source of iron, flourite, laterite, etc... I don't think the specifics matter that much...

Jeff


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## Raul-7 (Feb 4, 2004)

So I can just use biological media...like Ehfisubstrat(sp?), Matrix, etc.


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## JLudwig (Feb 16, 2004)

Raul-7 said:


> So I can just use biological media...like Ehfisubstrat(sp?), Matrix, etc.


Well, cost is an issue I guess also, but that I think would be great provided it is heavy enough to stay down... wet peat, mulm, pumice, carbon seem like good choices since they are cheap and stay on the bottom. Ehfisubstrat is a little pricey, no? I would avoid stuff like vermiculite, perlite, etc, as these things will prolly make a mess when you uproot stems.. Amano's powersand is mostly peat+pumice, I'm guessing that combo works for a lot of folks...

The most logical choice is soil, but there are some real issues with consistency... you're essentially creating a controlled low-octane soil.

Jeff


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