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Re: Lowering pH when adding hardwater nutrients



Woops! thanks Paul - I realised later that I meant to say the sodium bicarb 
provided carbonates (not calcium!), which somehow were needed for CO2 
production, but didn't get back to send a follow-up post.

David, I think I do have enough calcium in the water now, but not before - the 
snails' shells were pretty brittle.  Now with the Equilibrium, I am getting a 
reading of 20 ppm, which is fine, as you say.  Also, I've finally got a 
reading on the Iron test, chelated iron is .25 mg/L - its a happening thing!

>Adding ground limestone (CaCO3 and MgCO3) increases KH because some of the
  >calcium and magnesium carbonate reacts with additional CO2 to become 
calcium and >magnesium bicarbonate. These bicarbonates are more soluble, and 
the bicarbonate >ions increase the KH.

>The only way to keep an unbuffered tank stable is to change the water quite
>frequently. Any increase in the concentrations of nitrifying products will
>tend to "crash" the pH otherwise.

Okay Paul, I'll try to get some ground limestone.  Glad to know I don't need 
to bother with the acid, it was not something I was looking forward to.  And 
that idea about doubling the sample size for tests to increase the sensitivity 
is one I will certainly use!

>Umm - I just pointed out 1.5 KH as the "break point" for pH 7.0. A KH of 2 or 
so >won't throw you very much off. Especially since everything's being 
measured with >kits rather than electronically.

That's okay!

>Sounds like you're finally getting things where you'd like them.
>Much easier without the dolomite, eh?...

Absolutely - pH STILL 7.4!!!  Can't thank you enough, guys!

Susi
In beautiful, mostly sunny, Lions Bay, Vancouver