Finding balance in water management

[sSjey]

If the 'other minerals' react with acid, they're indeed part of the KH. That's why it's often referred to as alkalinity in the water industry. My water quality report lists various divalent metal ions like cadmium, copper, manganese, and nickel, which contribute to the general hardness, but it doesn't provide information on substances that react with acids, such as carbonates or bicarbonates. If there are naturally occurring compounds in the water supply that react with acid, they would be included in the KH. Off the top of my head, I'm not aware of any other substances besides bi/carbonate that would be present in the water supply, but that doesn't rule out the possibility of something else being there.

[kokomo]

@sSjey "And just to complicate matters, KH value is expressed as though it were all calcium carbonate regardless of whether the cation is calcium, magnesium or whatever and regardless of whether the anion is carbonate, bicarbonate or something else."

So if other minerals, like magnesium carbonate, are present in the water, do they also act as a buffer and help resist pH change? I'm wondering if they'd be just as effective as a high KH value that's mostly calcium carbonate?

[sSjey]

I'm still looking for evidence that calcium acts as a buffer in water. From what I've found so far, it seems that calcium only acts as a buffer within cells, not in water itself. If anyone has come across any reliable sources that contradict this, I'd appreciate it if you could share the links with me - I don't like being left in the dark about these things.

[kokomo]

I think I see where the confusion is - I was referring to the carbonates and bicarbonates of magnesium and calcium, not calcium itself. These compounds do act as buffering agents in water, helping to resist pH changes.