# Builder's tea



## Josgin (23 Jul 2020)

Hi, I have recently made a (hopefully) wildlife pond, like many recently I suspect. I had the 'bright' idea of
using bark from a fallen tree to clad it/hide the liner (see pics). Looks fine and natural, however the water
has become VERY brown which I found after some research is due to tannin from the dead wood (?).

Will aquatic plants alleviate this? If so what type? Thanks in advance for any advice.


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## mort (23 Jul 2020)

Hi, I'm not aware of any plants that remove tannins because I'm not really sure why they would need to but could be wrong. The best way to remove tannins is either by dilution, or chemical means (ie carbon). As this is a wildlife pond I would be tempted just to leave it for now as the stained water will help prevent algae until it's more mature and see how much the colour fades over the winter after rain. 
With the oak you will continue to get some staining for quite some time so it's easier to just leave it be for now and let nature take its course for a while, the wildlife won't mind.


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## Josgin (23 Jul 2020)

Many thanks Mort!


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## alto (24 Jul 2020)

Keep an eye on the integrity of the bark - if it begins to rot too much/too quickly you may have some issues with water quality (eg, low oxygen levels as bacterial activity may consume much of the available oxygen)

I suspect this will be a  blackwater pond for a good while


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## Josgin (24 Jul 2020)

Oooh! Thanks Alto... but what's a blackwater pond?


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## dw1305 (24 Jul 2020)

Hi all, 





Josgin said:


> but what's a blackwater pond?


One with lots of leaves and wood in it.  Ponds would naturally be surrounded by trees <"in most natural situations"> with dead leaves and woody debris present, <"tinting the water">. We often think of gravel pits, ponds and lakes in fields etc. with rush or grass lined edges, but that is a really recent development in evolutionary terms, and if they aren't continually grazed, or mown, trees will grow. 

cheers Darrel


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## mort (24 Jul 2020)

Josgin said:


> Oooh! Thanks Alto... but what's a blackwater pond?



Most people associated blackwater with tannin rich, botanic heavy waters in a tropical climate but its just a water body with dark waters created by leaching of darker elements. 

I've never really thought about it but perhaps the best salmon/trout fisheries could be described as blackwater due to their stained brown waters, @dw1305  ?


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## dw1305 (24 Jul 2020)

Hi all, 





mort said:


> best salmon/trout fisheries could be described as blackwater due to their stained brown waters


Certainly for Salmon, but it isn't really the blackwater that is important it is mainly because they only really still exist in rivers that originate in upland regions, and these are often peat stained. One of the advantages for the salmon is that these peaty uplands are relatively unproductive, which limits <"competition and predation">. The Salmon go to sea as quite small fish, where they feed up before returning to spawn. 

What we see now is a totally unnatural situation, and Salmon (& Trout, Shads, Sturgeon, Lampreys etc) would have occurred as a very common fish in nearly all of our rivers in the past. There are mediaeval laws restricting the <"number of days of the week"> that people could be fed Salmon. 

cheers Darrel


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