Re: ph problems

["David Shim" <David_Shim@MCKINSEY.COM>]

In your situation, I'd guess (and I'm no water chemist) that there must be
some basic or buffering agent in, or being added to, your aquarium.  R/O
water shouldn't stay neutral/slightly basic and resist acids/acid buffers
the way your aquarium water does.

I'd look at everything you've added to the aquarium as a potential culprit,
e.g.:

- certain water conditioners contain buffers, usually buffering to pH's
near 7.0.  Novaqua, for instance, buffers to 7.2 or so.
- many prepared fish foods contain added phosphates, which I'd heard could
build up and act as a buffer, absent adequate water changes (this might be
total hearsay)
- all aquarium gravel, decorations, fertilizer etc . . .

As for the Seachem buffers, I tried them with limited success.  I also have
very soft water (3 GH, <2KH), but not R/O, pH 6.8-7.0.  I tried to lower
the pH to 6.3 using the buffers, but the pH floated back up to 6.8-7.0
after two days (not overnight).  (Incidentally, it only took about 1/4 the
recommended dosage to achieve the target pH.  It's very surprising, in
contrast, that your pH bounced after you used full dosage.)

I spoke with the folks at Seachem, and they advised that absorption resins
used to control various organic wastes (phosphates, nitrates, proteins,
etc.)  could also absorb the Seachem buffers because the buffers contain
organic compounds.  They weren't sure exactly which products caused
problems, and they weren't sure the degree to which carbon also absorbed
some components of their buffer products.

The long & short of it was that I removed the phosphate resins I was using,
checked my water conditioner (no problem there) and tested the rocks, etc.,
and removed one, small culprit.  The pH took longer to climb back up, but
it still did within a week or so.  Without weekly addition of buffer (above
and beyond what you'd need to replace for water changes), I couldn't keep
the pH as low as I wanted.  I still have not figured out why, and resorted
to CO2 injection to maintain a stable, lower pH.

Gook luck!



>Last week I bought some Seachem Acid and
>Alkaline buffers.  I mixed them in the
>proper ratio to buffer the PH at 6.5 with
>dreams of going lower later.  I put only
>half of the recommeneded amount of the mixture
>since I expected that to be adequate
>for water as soft as mine.

>The ph went down to about 6.5 and then
>within twelve hours was back at 7.2.  I
>did not expect the bounce back in a buffered
>environment.



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