Water Chemistry Gh And Kh Questions

[pnyf]

I posted this in the Scientific section about a week ago without any help. But I have some questions about the hardness of my water coming out of my tap.
I was using the API hardness test and the GH turns green after 1 drop. This doesn't suprise me since the water here is very "soft" and it doesn't take much soap to wash dishes or anything.
On the other hand, the KH seems high - 9 drops to turn yellow.
Is it possible to have a low GH but a high KH? and what does this mean for my tank?
The water from the tap is a ph of 7.8 after sitting out 24 hours if it matters.
Thanks for the help. Its got me a little confused.

 

 

[TwoTankAmin]

Is there any chance you home has a water softener built in or some other form of filter?

 

[pnyf]

Not that I am aware of. I think anything done to the water is done by the city.

 

[TwoTankAmin]

Well I do know that municipal systems use a variety of methods for treating things, this can include changing GH.
 
And GH and KH measure two different things so, yes it is possible to have low GH and higher kH. These measures are evaluating different things in the water.
 
You can get a better idea about all of this by reading here http/fins.actwin.com/mirror/begin-chem.html#reference