# KH



## willson (23 Jan 2008)

Can anyone explain to me how its i possible that I have a KH of 7 in my tank. Yet my tap water is between 0-1.
Im adding no fertilzer or KH buffer only co2.

I find it a bit confusing!

Thanks


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## Dan Crawford (23 Jan 2008)

what gravel are you using? I believe that this can buffer the KH among others.


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## willson (23 Jan 2008)

Just dorset 3mm gravel (hope that makes sense).
Does bogwood buffer kh?


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## Dan Crawford (23 Jan 2008)

Am i right in saying that that is a natural beach gravel?
If so then the chances are that it is calciferous which will buffer your KH up. I think i'm right in saying that it will also buffer up your GH and PH.
There are a few "chemists" on here so they will confirm but i think i'm right?


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## willson (23 Jan 2008)

Gravel from the beaches and gravel banks of Dorset is a natural, tide rounded stone that makes an ideal aquarium substrate or base medium

That would be the description, so yes its beach gravel  :? 

Is it a problem having a kh of 7? Will it eventually drop after say a year?


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## JamesC (23 Jan 2008)

Yes it's your gravel that it raising your KH. Just keep an eye on it to make sure it doesn't get too high. 7 is OK but 15 is starting to get high IMO. Regular water changes will help to keep it down. Better to do small changes more often rather than big changes less often. This is to reduce shock for the fish. You may find it settles down a bit with time. A rise in KH will also raise the pH. The GH may also rise but this shouldn't be too much of an issue compared to the KH.

Your bogwood actually lowers KH so it is a good idea to have plenty to counteract the gravel.

James


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## George Farmer (23 Jan 2008)

Yep, the likely 'culrpit' is your gravel.

KH 7 is fine - around what mine is in my planted tanks.  

It well go up, rather than down, especially if you inject CO2 and the pH drops below 7.  This may dissolve the gravel and result in more CaCO3, so a higher KH.


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## willson (23 Jan 2008)

Im currently running co2 and the ph is 6.6 to 6.8. Im doing small regular water changes say 20% every five days. The KH will drop to 6, but soon be upto 7.

As for bogwood I dont think I could get much more in there


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