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Old 05-11-2004, 08:08 AM
 
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"Margolis" wrote in message
...


You keep saying that having these other phosphate buffers is not

normally
the case in an aquarium. But it seems to me that the reality is

it is more
common than not. Most people don't run RO water with just the

proper
minerals added. Most people start with tap water and then add

phosphate and
other buffers to it to dechlorinate it


Sodium Thiosulfate has no PO4 in it. PO4 does not dechlorinate.
PO4 is used for corrosion control in drinking water supplies in some
places, or as acid "buffers" for Discus tanks etc.

Better to use RO and low KH rather than acid "buffers".

is lower the ph to raise the co2 level. So it is safest just say

the chart
isn't accurate unless you are adding co2, imho.


I agree that you do not need the chart with non CO2 planted tanks, but
it's still accurate. Even if you have ann acid present, there is a way
around it to get a measurement that is reasonably okay.

People often hear to lower their pH to get the range of CO2 in their
tanks.
But they should onl;y add CO2 to lower their pH, not some other acidic
"buffer". CO2 is what the plants want, not some pH, so folks should
add only that if they want more CO2.

Otherwise approach the tank from a non CO2 prespective, don't worry
about it.
I just say don't bother, rather than saying there is something
inaccurate about the chart, that confuses an already confusing issue
for new folks and folks curious about using CO2.

One of the main purposes of a non CO2 tank is less mainteance. I do so
little to mine it really is pathetic that they look so good.

Your CO2 levels can be measured with the buffers present in a rough
manner also BTW sing the chart(eg PO4 "buffers", peat etc).

Take a glass of treated water and a glass of tap or Spring water etc,
add enough baking soda to get a KH of 2 or whatever you chose.
Measure both glasses pH/KH after 24 hours sitting out.

Say glass treated with acid has a pH of 6.4 and the spring water has a
pH of 6.8, both have the exact same CO2 content since they are both in
equilibrium with the air.

So subtract 0.4 pH units for your final pH/KH combo to find CO2.
The scale is not linear etc, but it's close enough and if you wanted
to play with math more, you could get very accurate. Close is good
enough for me, folks are too sloppy to have to nail a precise method
that has little wavering on either sideSo this is a semi practical
method that's easy.


Regards.
Tom Barr