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Re: deionized vs RO





whatever (actually, Michael Gray) wrote:
> 
> What are the pH and hardness of deionized and RO water?

The hardness is negligible, and the pH can be almost anything, as they lack
stabilizing buffers. My RO water has tds (not hardness) of about 30 ppm.
[Hardness obviously is lower than that.] DI should be even closer to zero.
Atmospheric CO2 will drive pH of either from 7 down to around 6 after
standing, but tiny trace amounts of anything (acid or base) can cause wild
shifts.

That's why we always temper it with tap water, unless breeding wild Bettas
or other oddballs.

On peat (previous post) it is useless for seriously changing water
parameters unless the water is already very soft and buffer-free. It will
slightly soften harder water, but will not change the tds or pH very much.

BTW, IMHO tds (total dissolved solids) is far, far more important than
hardness to the fish. It has a direct effect on the osmotic regulatory
process for their maintenance of body fluids. 99% of reported "pH-shock"
cases were probably from sudden drop in tds. That causes cells in gills to
explode as they take in too much water. Going the other way (to higher tds)
is dehydrating, but seems to be less fatal, usually. Drip acclimation to
major changes in tds is always a good idea. That allows the complex
three-level osmoregulatory process to adjust slowly to the new water.

Wright

-- 
Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot com

      To all gun-control advocates: Please just place a sign
      on your front lawn that reads: "This home is gun-free."

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