pH Buffer

[cloud]

Hi all,

Was hoping someone could explain to me what the buffer is? I know the basics, that it's the thing that determines how resilient your water is to sudden changes such as pH crashes and the like. But I figured it was high time I know more. Like how you test it's level in your tank, what effects it, what level it should be at etc.


Cheers

 

[Mako]

There are some confusing products out there. One is called "Acid buffer" and I don't believe it. Here's the most technical I can get on this.

"Buffering capacity" is what is often called "alkalinity" (not to be confused with "alkaline" in the pH scale) or called "KH" for the German word for carbonate hardness.

KH (buff. cap.) is basically a function of how much carbonate ions are in your tank. Good sources of carbonate are sodium carbonate (soda ash), sodium bicarbonate (the best, cheapest, aka baking soda), calcium carbonate, and several others.

ALL of these will raise the pH of your tank. They will also "hang around" in case any free hydrogen ions show up in your tank, which is what makes water acidic (think of HCl, hydrochloric acid, H2SO4, sulfuric acid, they all have hydrogen which can become a free hydrogen ion in water). Buffers will bind up the free hydrogen before (hopefully) it drops the pH significantly.


Test your KH with a simple, cheap KH test kit.

Keep in mind a high KH will usually also mean an elevated pH. Don't add a ton of baking soda to a discuss or neon tetra tank. Do so, however, in african cichlid tanks-- slowly and by monitoring.

 

[daveedka]

Check out Happychems chemistry article, and or any thread that discusses KH.
Kh or carbonate hardness is the basic way we measure buffer, a KH test kit will tell you your levels, and there are many easy ways to raise it if you need to.
Dave

 

[cloud]

Thanks guys. I've been measuring my kH for a few months now and it's constant. But glad to know what people are talking about when they refr to a buffer.