Water pH chemistry

I live in Netherlands in the very independent region of Friesland. One of the disadvantages of this is that my tap water has crazy high  pH value between 8 and 9. I already started thinking about using turf and other ways to lower pH to normal values. The first test I did was the pH test, which proved the value to be very high. After that I started reading about the ways to push this value down. I already knew that CO2 can bring this value down, but I was not sure how much and in what conditions. After some investigation I found out articles about  the relationships between pH, kH and CO2. To make the long story short, pH is not giving you the whole story. You may have very soft water (what normally corresponds to 5-6 pH) even when your water gives you readings of 7.5pH (normally considered normal, to lightly hard).The whole thing is that the real hardness of the water comes from kH which is the carbonate hardness. So there is relationship between kH, CO2  and pH, more CO2 less pH (kH is constant when you add more CO2, only pH goes down). So in my case I hoped to have normal kH (5-10dH). I run to quickly measure the kH in tap water and the result came 5dH. This means that the water has very little CO2 in it, as low kH and high pH means limited amount of CO2 in water (in my case around 1.5 ppm, where good value is between 22-28). Summarizing: check always both values. If your pH is over 7, check your kH, if it is lower than 10, you can simply add CO2 (check the tables online that will give you proper amounts, i.e. on Dennerle site) to lower the pH. If kH is very low < 5dH, make it higher as the pH can be unstable (little change on CO2 makes big pH change). If your kH is high, try to move it down - not pH, as whatever you will do, pH will go back to high values (or you will have to add big amounts of CO2, which will cost you a fortune and kill your fish). Make sure that you use quartz sand not lime (unless you want your pH up) and less stones, the better.

I hope it may be useful to you guys.

Cheers.

(P.S. I know that this topic is more complex as the whole thing depends also on another type of hardness buffers that may exists in your aquarium.).