# GH and KH



## kevinli1021 (Sep 9, 2010)

I have about 2 pounds of crushed coral in my aquarium and knowing that crushed coral is simply CaCO3 it can somewhat dissociate into its ions and raise both KH and GH while also increasing the buffering capacity around a pH of ~7.7. My GH=13, KH =7. How can I possibly lower both without affecting my pH? If I do decide to lower GH and KH does that automatically drop my pH because the three things are all linked together? Will I need to remove crushed coral (hopefully not) or will I have to perform frequent water changes in order to keep the GH and KH low and stable?

NOTE: I do not own, and do not plan on owning, a R/O system (unfortunately)


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## aniroc (Aug 23, 2012)

Ignore the KH. It has no direct impact on fish. It shows the buffering capacity of the water. The higher, the more stable the pH. 
Peat will lower both KH and GH, leading to more acid water. 
Same for driftwood. RO water (mixed with tap) does not add acids (like peat) and will also lead to lower KH and GH. It will not touch the pH if you have a good buffering in your tank.
API makes a "softener pillow" that removes Ca and Mg from your water (replacing them with Na) thus lowering the GH only.
Not sure if CaCO3 buffers the water at a certain pH. In order to raise the KH, we use bicarbonate (baking soda), not carbonate. There are also the phosphates buffers in the aquarium water. They stabilize pH at lower (more acid) values.


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## BillD (Jun 5, 2006)

What is it you are trying to accomplish? Why do you care about pH?


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## kevinli1021 (Sep 9, 2010)

It is for sulawesi shrimp tank.


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## LTPGuy (Aug 8, 2012)

kevinli1021 said:


> It is for sulawesi shrimp tank.


You might want to read this thread if you had not already...
http://www.gtaaquaria.com/forum/showthread.php?t=39539


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