Kh value

[PowderTang]

Hi , will increasing the pH also increase the kh value?

I have been increasing the pH with some pH buffer, but realized that my kh value is far too high...so I wonder is there any relation?

Because I use salt mix water, the pH tends to be low...so I have to increase the pH using pH buffer...but how come my kh value is still so high ?

How do I reduce it?

Thanks

[Powder blue Tang]

What kind of salt you are using ? Frankly i don't really bottle about the PH but KH, as my reef's friend said as long as your KH between 7-10, your Ph won't swing too much one.

Happy reef !

[PowderTang]

Ok I realized why it is high It's because I increase the pH using pH buffer. Yes now kh is reduced during water changes...but then I test pH again, pH dropped to like 7.8 ! If I increase the pH, the kh will increase again Anyone has come across this problem ? Or is there anyone with pH above 8 and yet kh is normal ?

[Stanley Goh]

Maybe u can share what products u are using , perhaps senior reefers can share their advice clearly ... I'm also learning here , I use Red Sea powder for KH , cal , mg ... My tank ph 8.2-8.3 ...

[pcw]

My pH is around 8.2 and kh is around 9. PH is a measure of the relative quantity of H+ ions and kh is the measure of the water's buffering ability. An increase in kh is usually done with carbonate salts. The salts of weak acids give relatively alkaline solutions when dissolved. The buffering capacity of a reef tank is mainly done with the relative concentration of carbonate ions and is an equilibrium with the corresponding acid(arguably carbonic acid or maybe just carbon dioxide). I'm not too sure what product you are using to raise the pH but it could be a dilute solution of sodium hydroxide. It will raise the pH but not directly affect kh (unless it manages to react with sufficient carbon dioxide dissolved). I suggest using sodium bicarbonate or sodium carbonate to raise kh.

[PowderTang]

I'm using API proper pH 8.2 It says increases carbonate hardness kh to hold pH 8.2 I did a control test amid I found out increasing the pH will increase the kh as well Is there any product that can increase pH but will not alter the kh ?

[pcw]

Carbonate salts and the corresponding acid result in a buffer solution at the proper concentrations. Increasing the pH may theoretically also increase the kH. Theoretically because the alkali that you add will most likely react with some co2. I do not think that the increase in kH through the addition of NaOH will be dramatic though. Adding sodium hydroxide is dangerous because its a strong alkali that can cause the pH of the entire system to shift dramatically though. As for which products use NaOH only, I'm not too sure. Unlikely to get it off the shelves though because its a strong alkali and is very caustic.