We have weird water in Austin. It's very alkaline (above 8) with a moderately hard GH, but the KH is for khrap, which means virtually no buffering capacity, which means big pH swings and crashes are very possible. Weekly water changes can help restore buffering capacity, but I've found I need to add a bit of baking soda during water changes to keep the buffering capacity up. Just a tad, though, because too much baking soda seems to drive the pH even higher.
I'm not necessarily looking to test KH in particular. I'm looking to test the water hardness.
I want to test the water hardness for two reasons:
1. I have read that it is better to purchase fish based on the tap water conditions that you have. So I am trying to test my tap water to find out what I have. This way I can match the fish to the water, instead of vice-versa - buying fish and then trying to change the water to match their requirements.
2. I have read that some water hardness is a good thing, since it buffers the water and prevents pH swings. So I am trying to find out if my water is hard or soft.
Thus, I am trying to figure out what I need to test for. I now know that KH and GH are two different water hardness tests. I am now trying to understand if I need to do just one of them or both of them - and why.
FYI: I did a pH test on my tap water (using the API Freshwater Master Kit) and it came out at 7.8
I'm not necessarily looking to test KH in particular. I'm looking to test the water hardness.
...
Thus, I am trying to figure out what I need to test for. I now know that KH and GH are two different water hardness tests. I am now trying to understand if I need to do just one of them or both of them - and why.
I am a beginner and did some reading on this.
The way I understand it, you test for KH to see how stable your pH is going to be. This is the alkalinity value. If you have a high KH and high pH, that high KH is going to resist downward changes in pH, so it will be more difficult to modify the pH. You'll need to lower the KH first. But don't lower it too much or else you'll get sudden wild swings of pH. So, testing for KH and modifying it are part of adjusting between acid and alkaline pH's.
The GH can probably be considered the softness/hardness value, equivalent to the dH quoted on fish profile pages, except for a conversion factor. Strategies that lower pH may also lower this, or they may not. I can't seem to find the conversion formula between dH and GH but there should be one.
