Re: pH vs. TDS

[Mike & Diane Wise <apistowise@fgn.net>]

For me, with tap water with a KH of 1.5º, the increase in conductivity is almost
negligible. For people with really hard water, the pH can only be lowered by
removing carbonate hardness. This will require more acid than in soft water, and
the increase in conductivity is not a good idea. HCl doesn't increase the TDS
very much because chloride ions are not a strong hardening agent. Chloride ions,
however, will raise the electrical conductivity considerably. I wouldn't suggest
using HCl to lower pH without checking to see what it does to your conductivity.
For most soft water fish, increased conductivity is just as detrimental as high
hardness.

Mike Wise

Jody wrote:

> Mike,
>
> This is really helpful stuff.  A question, though:  Do you find that a
> simple chemical lowering of pH is as effective as lowering TDS or
> conductivity?  Using the acid is much easier - assuming all the necessary
> precautions are taken - than going the RO route.  I guess it boils down to
> softness (or low TDS) vs. acidity.  And, I guess the effectiveness should be
> measured for this purpose by gauging the effects on fish for health and/or
> spawning activity.
>
> Thanks,
> Jody
>
> ----- Original Message -----
> From: "Mike & Diane Wise" <apistowise@fgn.net>
>
> > This is a concentrated form of HCl, 37% by volume.
> > This is extremely caustic. It dissolves holes in
> > most clothing, corrodes most metal surfaces, & the
> > fumes will damage your respiratory system. This
> > acid should be kept out of the hands of children
> > and people too stupid to handle it properly. I
> > store mine in a locked wooden cabinet, sitting on
> > a piece of slate. To use it for testing dilute it
> > 1 part acid to 7 parts water. ALWAYS add acid to
> > water. Do it the other way & it may vaporize the
> > water and splatter acid. I have also used it in a
> > concentrated form to lower the pH in my soft
> > water. About 5 ml of concentrated acid will drop
> > the pH of 20 gallons (75 liters) of my tap water
> > from 7.4 to 5.0 instantly. Obviously I mix in in
> > vats, not my aquaria.
> >
> > Mike Wise
>
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