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I was hoping for some answers about pH, buffering, and hardness.

It seems like the correct approach to changing pH is to add a buffering agent that will buffer the pH of the tank to the desired value. So, let's say my tank is 7.6 (which it is) and I want it to go to 7. First I need to chemically remove the original buffer - let's say by adding an acid that forces it to precipitate out, and then continuing until the tank is at 7.0. (There are no fish in this imaginary tank.) Then I would need to add a buffering agent that will keep the tank stable at 7.0 against both pH rises and falls. Hardness fits into this theory as minerals that tend to buffer pH at basic levels, say 7.4 to 8.2.

Is this right?

Hi,
Well your use of some chemical terms such as
"precipate out" bother me as there will be no
participate. And, your thought of using
chemicals and then chemicals to counteract the
chemicals, and so on, could be disasterous to
the fish as you cause the conditions to "yoyo."

If your tank is 7.6 (which is great, and needs no
"fooling around with), and you want it to be
around neutral (7.0), then yes, you can add
chemicals (pH down, for instance) and then
with each water top off (for evaporation) and
water change, some additional "adjustment" might
be necessary. Then, when the city changes wells
or water sources (about every quarter, to
semi-annually) you will have to test, retest,
and go through the same cycle again for new
readings.

In the long run it is easier, less expensive, and
easier on the tanks inhabitants, if you do it
"naturally" using peat, for instance.
Also driftwood will lower the tanks pH, but there
is no way to say that a 6 inch piece will drop it
0.x. Some affect the pH more than others and all
over time loose their "punch" as the tannic acid
leeches out.

If you want it to stay at 7.0, put a handfull of
peat in the filter, or if you want it to stay between
6.0 and 7.0 put a layer of it under the gravel.
The easiest way to "regulate" it is to use it
in a filter that is easily accesable such as a HOB.
Start out with a small amount, let things stabilize
and then add some more, if necessary.

10 & 20% water changes will shift the pH slightly
as the new water is higher than the tank water,
but it will make no difference to the creatures
in the tank, and the water, as it cycles through
the filter, will drop over time back down to the
7.0 target.

You seem to be placing too much emphasis on the
magic number of 7.0. You really don't need to
do anything to the tank. And, as the tank ages
it will turn more acidic anyway.

Frank


[span class="edited"][Edited by FRANK 2004-08-12 09:13][/span]

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I mean "chemicals" in a broad sense, so peat moss, crushed coral, driftwood would all qualify, more or less, since they all either leach chemicals into the water, or absorb them out of the water.


[span class="edited"][Edited by Silverlight 2004-08-12 09:55][/span]

Hi,
In a broad sense, yes.
Crushed coral, dolomite, limestone, or crushed
oyster shells will affect the water similiarly.
Dolomite has more Mg in it than limestone so that
too will be added into the mix.
Peat and driftwood, will give off organic acids
and push the Ph into the acidic region.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I had problems with my ph as well. I admit that I got lazy and did not check my water chemistry for 3 months. When did check the ph was 6.0. I KNOW.
I was still doing the water changes, yet it still got that low. I have added dolomite and crushed coral. I can now only maintain a ph of 6.8
I have chiclids in tank. Do I need to add more of buffers in tank?