On Tue, 20 Jan 2004 20:52:22 UTC, "RedForeman ©®"
wrote:
baking soda is/can be added as a buffer, it raises your kH and buffers your
pH enough to keep a stable pH for quite a while... I add 1 tbsp to every
10g, do your own math, and it gives a bump on pH and the buffer capacity is
in the volume you add... the more you add, the more your kH raises, but not
pH
If you don't have CO2 injection, raising the KH must always raise the pH.
(Well, there are a couple of exceptions, but they're not of any use in
keeping your neons alive.) This is because there is a fixed amount of
carbonic acid in your water, determined by the amount of CO2 in the air.
The pH depends on the ratio of bicarbonate to carbonic acid; so increasing
the bicarbonate with the same amount of carbonic acid gives you higher pH.
Your fish and plants complicate this by moving CO2 in and out of the
water. But the atmosphere is always pulling the CO2 level back toward the
3-4 parts per million that's in equilibrium.
for a planted tank, well, that varies IMHO.... I shoot for a pH of 6.6-7.6
on 3 different tanks the lower one has CO2, others don't
pH 6.6 and kH of 2-4 give you a range of 15-30ppm of CO2
pH 7.6 and kH of 2-4 give you a range of 1-3ppm CO2
One thing is left out of this: if you don't have CO2 injection, your CO2
level *will* be set by the amount of CO2 in the air; 15-30 ppm is not
going to happen, because it's out of balance with the atmosphere. You can
mess with it, for instance by adding acid to the tank to bring down the pH
and increase the CO2; then some CO2 will escape from the tank into the
air, and the pH will go back up to nearly what it was before. "Nearly",
because the KH went down a little when that CO2 escaped into the air.
Use this to find your CO2 levels and what is optimal for your tank and
water...
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
But remember -- not to belabor the point or anything -- that if you don't
add CO2 to the tank, your CO2 level will be 3-4 ppm. This means KH of 1 -
1.3 at pH of 7.0. A pity, because neons are happier at 7.0 than at 7.8.
There are buffering chemicals that will supposedly keep the pH reasonably
steady at 7.0 or so; if you use these buffers, just forget about KH and
CO2, because you're overriding them.
--
Dan Drake
http://www.dandrake.com