"Racf" wrote in message link.net...
I added
po4 yesterday to my tank in the form of ph down. Will my co2 reading
now be
void because of that buffer? Surely the plants will consume the
phosphate
pretty quickly, If I do a water change over the weekend and do a co2
measurement will it be more accurate? How do you balance things out
between
buffers and co2?

I thought pH down was diluted Sulfuric Acid, which I think means its not
Phosphate and does not contain Phosphate.

H2SO4 will destroy KH. I don't think it would be a good thing to add.
It'll low pH by removing the buffer.

Some older and newer pH Down products are PO4 based, the old stuff is
H3PO4, 30% phosphoric acid.

You'll see bouncing of the pH by using things like these in
conjunction with CO2.

All you do if you need to control pH:
Baking soda(to raise KH), CO2 to add for the plants.

Baking soda, (the KH) is the buffer, the CO2 is the acid.
The ratio of both of these determines the pH.

If you are adding PO4 in this form(the acid H3PO4 or PO4 based etc),
the small amount needed for plants is not enough to influence the pH
in a planted tank. A 20 gallon tank might need a drop or two 2-3x a
week etc. That's not much.

But do NOT use acids like HCl, H2SO4 etc to lower pH in a planted
tank, use CO2 gas, plants don't grow on HCl etc, they grow on CO2, so
give them this specifically along with some HCO3(from the baking soda)
if your KH is less than 2-3 degrees or about ~50ppm or so, and nothing
else for pH/CO2/KH.

Regards,
Tom Barr