Evening star., 1936-12-19

not handled with the maximum OF
knowledge.
In time q deposit forms on the inner
glass, subjected to the action of the
water and the chemical formulae formed
as the result Of reaction of fish on water
water on fish, fish on plants, plants on
sand, etc.
There is whole string of these
chemical actions and reactions. Some
of the products formed actually enter
the bodies of the fish through the ac-
ton of osmosis, or the passage OF sub
stances through a thin membrane.
In such a chemical laboratory, so
confined, so restricted, much damage re-
suits inevitably. The inner sides of the
glass walls receive deposits, some of
which can be removed, some of which
are removed with great difficulty, or not
at ALL
Growths of algae, minute plants, re-
sulting from the action of light, aided
by tiny food particles in the water, may
be cleaned off the glass at first with a
piece of absorbent cotton, later with a
razor blade.
But the chemical deposit from the
water itself is another matter entirely.
At first even these may be taken off by
the sharp safety razor blade. AS time
goes on, however, they harden to a de-
gree which makes them almost part
of the glass.
Enough of this deposit may be re-
moved to give the enthusiast the idea
that he is getting rid of it entirely.
Even if he takes the entire tank down
and cleans the walls with salt, he fails
to remove the last vestige.
Such deposits tend to give the tank a
rundown aspect. When this is COM
bined with ill effects Of old sand, the
result is an altogether unlovely aquarium.
What can be done about it?
The main thing is to give up the idea
that one should try to make a given
tank, and a given 'set-up," last as long
as possible.
The next is to realize that aquarium
sand as commonly used, is a material
which needs renewing completely at
least every two years.
1t is possible, by washing it in boiling
water from time to time, to get it as
clear, seemingly, as the new, but this
is mostly deception. There is a deposit
there, not only on the surface, but even
back in the very pores of the grains
Once it is put back in the water it
tends to set up the same old reactions
and to be that last straw which breaks
the well-known camel's back.
Since sand is almost the least ex
pensive material which enters this COM
paratively inexpensive hobby, it is only
the part of wisdom to purchase new
sand every now and then, especially if
you feel that the tank is going back
but at the same time you do not know
exactly why.
When tank fishes sand and water all
grow old together, there is every reason
to feel that an entirely new tank may
be needed. too. An average good
aquarium should last for years. but in
practice it is often found that the best
of them. constantly inhabited by per-
haps too many fishes, need to be dis
carded in about four years. There will
be exceptions. of course.
If fishes are kept we'll enough to
enable them to live long. they should
be given a brand-new tank every three
or four years, with completely fresh
sand at least twice in that time; once
year would be better. with fresh plants
whenever the old ones do not seem up
to standard.
Keep your eye on the sand. That way
aquarium wisdom lies.