BUFFERS
by Bart van Dijk
First published in the newsletter of the Vancouver Aquatic Hobbyist Club
Aquarticles
That darned old Dave ! Here we are, all lying down, still huffing and
puffing after that 3000 foot climb, yet he is fully ready to go to work. Ya , Dave was the
oldest guy on the crew, but he could leave all of the other five crew members behind on
the climb up to the survey line...
Years ago, we were doing the original location work for the 260
kilovolt hydro line high up in the Lillooet River Valley. How come a six men survey crew,
you ask? Well, - those were the good old days before the power saw, when men were tough
and clearing a line through the bush was axe work. Three thousand feet cleared with about
a hundred trees chopped down was about the average day's production. And again that Dave
in his sixties could out-chop twenty-six year old me, his falling partner, any time. I
would take my axe home at night instead of leaving it in the bush, (which meant
having to carry it back up the next day), and spend hours filing and honing, just to get
that angle of cut exactly right and be determined that tomorrow I would do it - at least
for once have the bottom cut ready long before Dave was even near ready on the top cut.
But all that summer I never made it. He would take at least a couple of minutes changing
his breathing to his chopping rhythm, while I was already chopping with all my might; and
then that maddening rhythm would start : first chop, cut; next chop, a huge chip would
fly, and it simply would not stop. Every second blow a chip, continuing for the full
depth of the cut; and some of those trees were three feet in diameter . My axe would get
stuck, my muscles would ache, my lungs felt like they were on fire, and so on and so
on . That Dave had his body fine-tuned like a superb athlete.
Thinking about it now, the similarities
between keeping a fine-tuned aquarium and a fine-tuned athlete are all there. By breathing
deliberately beforehand, Dave would not wait for the body's response to too much carbon
dioxide in the blood. His blood would be charged with the maximum oxygen possible , and
would be ready to take away all the carbon dioxide and lactic acid that his muscles would
develop . He had learned how to take care of the fluctuating pH levels in his blood. I bet
his pH never came close to the maximum allowed of 7.8 or anywhere near the minimum of 7.0,
thus never giving his buffering systems more than a normal load . Meanwhile my muscles
were screaming with the pain of the acids my blood would not take away. All my buffering
systems were over-charged with acids, and my breathing would become laboured, interfering
with the cooling job the blood was responsible for. I simply had to stop for a few minutes
to allow things to settle down to a more even level. Meanwhile the chop, chop of
Dave continued at that maddening even rhythm.
Hey, what did you say? "Buffering"? What
is that exactly ?
A buffer is an absorbing medium . A
buffer zone beside a highway absorbs noise and destroys it. A wind buffer absorbs and
deflects the storm winds. A buffer on your computer absorbs an overflow to your printer or
to your modem and releases the information when they are ready for it. This allows them to
do their job at a more leisurely pace.
The human body uses the lungs, the kidneys, the liver and the bowels to
rid itself of unwanted (toxic) waste products, but each works at its own pace . The
bloodstream is extremely susceptible to rapid changes. The flight reaction, or even having
to climb a stair on a quiet walk, means having to take care of massive amounts of acids,
which if unchecked, will lower the pH very drastically and rapidly. A combination of a
weak acid with a similar amount of one of its salts is a chemical buffer, capable of
absorbing the wildly increasing concentration of positively charged hydrogen ions (or in
the opposite case absorb the rapidly increasing concentration of the negatively charged
hydroxyl ions [OH negative ] ). Generally, the weak acid takes care of the increase in the
basic parts of water and the salt takes care of the acidic parts.
Here is the good news… The same buffers our blood
uses work very well in our aquaria.
The very ,very soft Vancouver water, which because it is so soft has
minimal natural buffers and thus is very susceptible to wild pH swings, needs buffers. We
all have our pet remedies for the long term control of pH levels. (In aquaria they want to
go to the acid side).
Here are some listed roughly in order of rapidity of the action:
a spoon of baking soda (or avoiding sodium, potassium bicarbonate), garden lime, ground
limestone, a small chunk of limestone, some beach sand with broken shells, some coral sand
or a small piece of coral in the tank. And you know what ?… Each one of these,
together with water and the carbon dioxide our fishes produce, will form the first buffer
combination the blood uses: carbonic acid and sodium bicarbonate (H2CO3 + NaHCO3).
In our aquaria, as in the blood, the quantities of each of these
chemicals is constantly being assaulted. Lights come on in the morning and our plants
switch from producing carbon dioxide and using oxygen, to using carbon dioxide and
producing oxygen . Our fish rapidly increase their production of carbon dioxide and their
use of oxygen .The plants are extremely aggressive in their quest for carbon dioxide and
will even strip all of the nicely built up buffer. And here is the blood's second system,
the Phosphate System (NaH2PO4 and Na2HPO4). These two buffers take the pressure off the
blood's two primary systems; getting rid of carbon dioxide by the lungs and the selective
expulsion of excessive chemicals by the kidneys.
NOTE : You are the one mainly responsible for similar functions in the
aquarium . You are responsible for reducing carbon dioxide levels by disturbing the water
surface with your air pump and removing excess chemicals by regular water changes.
|