# Gh/kh and tannins question.



## NOWIS (10 Jun 2019)

Hi all I was just wondering if high kh/gh has any affect on the amount of tannins released by wood or substrates like ada Amazon? 

Ada recommends using soft water for water changes to stop the release of Tannins. 

Any thoughts or info would be great thanks.


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## alto (10 Jun 2019)

I have very soft tap water - tannin release is dependent on the wood piece, some seem to release a lot of tannins, some very little I have some very old, very dark wood that also (still!) releases a dark tarry substance 

Generally woods will release more tannins initially, then taper off to some minor level

When planning a wood heavy scape, some will presoak the wood for several months, then brush to remove loose fibres


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## Keith GH (10 Jun 2019)

Simon Hellmich
Tannins are in many timbers and when immersed in water they are realised.  Presoaking does remove most in many timbers but there are a few timbers that continue to realise the tannins no matter how long it is soaked.   

Keith


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## NOWIS (10 Jun 2019)




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## NOWIS (10 Jun 2019)

thank you for your reply’s 
I understand most Timbers release tannins. I am interested if kh has any affect on it as the info on ada soil says thanks


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## zozo (10 Jun 2019)

Simon Hellmich said:


> I am interested if kh has any affect on it as the info on ada soil says thanks



Well Kh is carbon based buffer capacity of the water.. This means it buffers/nutralizes acids, acid bind to the carbonate and it releases co².
If you have high kh you need more acid to lower the ph, in low kh it needs less. But as said the kh nutralizes the acids and when it's done that it's about back to normal again than again acid needs to be added. The changes after nutralisation with little amounts are hard to determine, not realy measurable with household/hobby equipment. A little bit of tanins comming from a piece of wood or a dead dried plant leave coloring your water yellow also realising some tiny amounts of humic and fulvic acids, maybe only has +/- 1% effect on altering kh and ph values.

You would need a bit more than a piece of wood and very soft water to effectively measure changes.

You might be intersted in reading this blog.
https://tanninaquatics.com/blogs/the-tint-1/humic-substances-in-freshwater-aquariums

ADA soils are packed with i guess added goodies that can alter these values.. But it doesn't do this indefinitely. Doing water changes will finaly flush it all out. And than you have to go with what commes from the tap.


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## NOWIS (10 Jun 2019)

Cheers @zozo for your detailed reply. part of the answer I was looking for was also in the blog


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