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Re: hardness terminology and oops.
Andy Moore wrote:
> Could someone explain the difference between Calcium Hardness & Alkalinity.
> Do they correspond with each other in some way ?
Alkalinity measures the buffering capacity of water. It is what Tetra
calls "carbonate hardness". Alkalinity usually reflects the concentration
of bicarbonate in your water. Phosphate, EDTA and some other organic
acids can also be measured as part of alkalinity, but usually at
I rarely hear anyone refer to "calcium hardness". Total hardness, general
hardness (I think that's the term used by Tetra) and calcium+magnesium
hardness all refer to the same thing. What you're thinking of might be
the same thing as total hardness or possibly just that part of it caused
General hardness measures the concentration of ions in the water that react
with soap to make scum; those are magnesium and calcium mostly, but
officially the measure also includes strontium, barium and radium.
> One of my Tetra kits (KH) reads Carbonate Hardness ? Is this the same as
> Alkalinity or Calcium Hardness ?
> Getting confused !
Carbonate hardness is alkalinity.
In modern professional water quality literature the term "hardness"
always (at least as far as I have read) refers to the calcium+magnesium
variety of hardness. That avoids some confusion.
The fact that alkalinity and hardness are express in the same units (and
odd units at that) adds to the confusion. As I understand it, we use the
same units because of the importance of the two measures in boiler water.
You can compare an alkalinity number and a hardness number and select the
lower of the two. That value indicates how bad the mineral deposits in
your boiler will be. Doesn't relate much to aquaria, does it?
The folks authoring literature for the hobby would do us all a favor if
they limited use of the word "hardness" to refer only to calcium+magnesium
hardness. Their current usage is confusing.
Cindy double posted, then apologized:
> oops, still learning the ways of e-mail
Well, I suppose you'll be suprised to learn that your mail-reading
software double-posts everything you send. It sends a two-part message;
the list gets one copy as normal text and one copy as a larger HTML
document containing the text. You're reader probably only shows you one
So, you sent two. I got four. You "oops"ed once. I got it twice.
You aren't the only one on the list with software that does the same
thing, and probably most of you don't realize it. Personally I find that
it severaly reduces the readability of the list - almost as badly as
quoting entire digests in replies. Sending encoded rich text or other
word processed documents has the same effect.
I am speaking only for myself in this -- to anyone (not just Cindy) using
web browsers, word processors or other software that can send formatted
text, *please* try to get your software to send only plain text copies of
your mail. Plain text is the closest thing we have to a standard format
and anything else is going to waste space, time and bandwidth.
Grumbling on a drippy morning in Albuquerque.