Re: pH hell

["David A. Youngker" <nestor10@mindspring.com>]

Alex -

Take a deep breath, hold it, then let it out slowly. Do this a second time
with your eyes closed...

We understand the reasons for your having to play chemist. That's not the
problem. Forget the explanations and concentrate on the information that
Dave Gomberg's trying to gather from you. You're the only one holding all
the cards here, and they're fairly close to the chest right now.

You want to know what's going on with the buffering in your tank. That
requires knowing as much of everything that's physically involved as
possible.

The values of your tap water gives us a *known start point* from which to
guage the effects of all adjustments made. The third letter finally states,
"tap water >190 ppmCa, Mg,130ppm HCO3(straight from the tap), pH 7.6, KH
7-8, GH 9." OK, now we know where it all started.

Dave then asks the values after RO. You state that you use a deionizer, but
you never say what type of water it provides. Knowing the output values is
important in order to determine if it's a single-resin (sodium/potasium
rechargeable? disposable/replaceable?) or dual-resin, as they both affect
the outcome in different ways. You never give these values, but go
immediately into what you add to the water. Speaking of which, when it comes
to all of these additives, it would help to know a little more than the
following descriptions:

"phosphate- and nitrate-free acid/base buffer" Is this a combination of
separate buffers or a mixed single product design to "pinpoint" a specific
pH? For that matter, what *is* the product?

"adding acid buffer to bring it down and stabilize it" Another product? One
of the components of the above? Again, what *is* it?

"I add Kent R/O Right to correspond to GH 3" Does this mean you're shooting
for a GH of 3, or are you adding 3 degrees of hardness? This is one of the
times it would help to know the values of your deionized water, especially
when followed by statements like, "The original water in the tank used to be
2/3 deionized and 1/3 tap.  This gave me GH 5 and KH 5 when I used Mardel
Waters of the World South American to lower the pH to 6.8"  It's an "Is
adding the Mardel's affecting the hardness?" kind of thing...

"So, I  began to make water changes using an alternative buffering system."
Again, this doesn't say anything usefull.

"Right now, after titrating non-phosphate buffered acid into the tank, the
pH has stabilized at 6.6." Acids aren't buffered - a combination of an acid
and one of its salts create a buffer, however. And a non-phosphate acid
doesn't narrow the possibilities to a usefull working set, either. Sulfuric?
Hydrochloric? Acetic? Ascorbic? Floric? Get the picture?

"Part of the buffering system is just sodium bicarbonate.  I'm not sure
about the buffered acid." Is this refering to the acid/base buffer you
mentioned before?

"Once I have reconstituted it, the pH is 6.6 GH 3 KH 3." Well, at least we
know some of the *ending* values after doctoring...

Just how many different things *do* you put into the water anyway?

-Y-

David A. Youngker
http://www.mindspring.com/~nestor10
nestor10@mindspring.com




-------------------------------------------------------------------------
This is the apistogramma mailing list, apisto@majordomo.pobox.com.
For instructions on how to subscribe or unsubscribe or get help,
email apisto-request@majordomo.pobox.com.
Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!