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Re: Lowering pH when adding hard water nutrients to soft water

> Date: Fri, 1 Sep 2000 08:09:07 EDT
> From: IDMiamiBob at aol_com
> To keep it as simple as possible, I recommend you reduce the sodium 
> bicarbonate to give you a KH of 3.  The more you have, the harder it is to 
> move pH down.  Then use simple hydrochloric acid to bring the pH down.  This 
> way the only negative ion you are adding is Cl -, which is not a problem at 
> the levels you will end up with.  

I'm puzzled, confused, ignorant or perhaps all three to various degrees. 

KH adds bicarbonates to the water as well as sodium ions. Bicarbonates are a 
buffer. When you add acid to water with bicarbonates, the H+ ions generated when 
the acid dissociates combine with the bicarbonates to form, um, water, CO2, ???. 
But the end result is that bicarbonate is "destroyed" by the act of buffering.  

So you add "too much" sodium bicarb and the pH goes above where you want it. 
Then you "neutralize" the excess by adding hydrochloric acid to get the pH back 
down to where you actually want it (by reducing KH!). 

So, the end result is you now have extra sodium and chlorides. Is this the idea? 
Jeez, why not just add salt - it cheaper and safer. 

George Booth in Ft. Collins, Colorado (booth at frii_com)