# How would you build blackwater-walstad tank?



## Garuda2520 (May 2, 2021)

The headline says it all.. How would you build a blacwater biotope aquarium. I have been intertaining the idea that my next project would be a blackwater biotope aquarium with soil, no filter.

Would it be possible to replace most of the plants in the soil by adding aerial growing plants with roots in the water?


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## dwalstad (Apr 14, 2006)

Rooted plants need soil. Soil needs rooted plants. If you don't have rooted plants, don't use soil. Just put a scattering of gravel or sand and a few stones on tank bottom. Add floating plants or epiphytic plants (Java Fern, etc) attached to rocks and driftwood.


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## Garuda2520 (May 2, 2021)

dwalstad said:


> Rooted plants need soil. Soil needs rooted plants. If you don't have rooted plants, don't use soil. Just put a scattering of gravel or sand and a few stones on tank bottom. Add floating plants or epiphytic plants (Java Fern, etc) attached to rocks and driftwood.


Thank you  Do you think floating plants, java fern would be enough to handle the water and keep it safe for the live stock without filter?

What about the roots of aerial plants as filtering the water? Do they work the same way as as floating plants?


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## Michael (Jul 20, 2010)

You could use rooted plants that grow through the surface of the water, called emergent plants or "aerial advantage" in Diana's book. Many common aquarium plants will do this as well as some houseplants. These will keep the soil from becoming anaerobic.


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## Endler'sGame (Aug 25, 2020)

It probably defeats the purpose of low tech to have a sump, but that's one way to do a low-planted blackwater setup without a true filter; a spare 10 gallon full of something fast growing like hornwort could be a nutrient sponge without affecting the aesthetics of the main tank.

And no reason the sump has to look like one, right? Just a reason for another tank, as if any of us need a reason.


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## Garuda2520 (May 2, 2021)

Endler'sGame said:


> It probably defeats the purpose of low tech to have a sump, but that's one way to do a low-planted blackwater setup without a true filter; a spare 10 gallon full of something fast growing like hornwort could be a nutrient sponge without affecting the aesthetics of the main tank.
> 
> And no reason the sump has to look like one, right? Just a reason for another tank, as if any of us need a reason.


I like your idea, this one could be an interesting project to do.. 👍🏻


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## jatcar95 (Oct 30, 2019)

Garuda2520 said:


> I like your idea, this one could be an interesting project to do


This is a super neat idea, yeah. Please keep us updated if you do decide to go that route


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## dwalstad (Apr 14, 2006)

Garuda2520 said:


> Thank you  Do you think floating plants, java fern would be enough to handle the water and keep it safe for the live stock without filter?


Yes, if you have enough floating, emergent, and attached plants. Main thing is to have enough light to get good floating plant growth. If their growth isn't luxuriant, I would consider adding a trace element fertilizer. Because they have the aerial advantage, floating plants can do a dynamite job of water purification.


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## Garuda2520 (May 2, 2021)

dwalstad said:


> Yes, if you have enough floating, emergent, and attached plants. Main thing is to have enough light to get good floating plant growth. If their growth isn't luxuriant, I would consider adding a trace element fertilizer. Because they have the aerial advantage, floating plants can do a dynamite job of water purification.


Thank you again Diana 😊 This was my original plan also. I think that roots, floating plants and attached plants can make tank seem as authentic blackwater habitat. Then it's possible to cover gravel with dead leaves also..

I think my project is starting to form piece bu piece..


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## Noahlikesfish (Apr 17, 2021)

Get like a 2 inch layer of leaves and get 12 dwarf corydoryas or aspidoras


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