AIRSTONES
By Gerry Hawksby
From the Ryedale Reporter, newsletter of the Ryedale Aquarist Society, Yorkshire,
England
Aquarticles
We all use airstones at sometime during our fishkeeping experiences. Some of us may
graduate to the more efficient external canister type filtration systems, making airstones
a thing of the past, but for those of us who still use the simpler forms of filtration
then airstones remain an important piece of equipment which, in order to ensure optimum
filtration within the tank system, we must ensure are always working efficiently.
Airstones come in different forms and are made from a variety of materials. The most
common airstones are the inch long cylinder and ball shaped ones that are used in under
gravel filters and some types of corner filters. Airstones are available up to 12 inches
in length and these particular models are designed to either be of assistance in aeration
or to be used purely as a decoration in larger tanks. The airstones mentioned up to this
point are usually made from either a glass or sand material. In recent years we have seen
the appearance of an 'everlasting' model but more about this later. On the shelves of
aquatic retail outlets you may also find airstones made out of wood, but these are only of
use to those aquarists with a marine set up.
Whichever type of airstone you prefer to use there will come a time when the production
of bubbles begins to tail off. This is an indication that the crevices between the glass
or sand particles are getting blocked. It is time to either put a new one into use (you
should always have a spare airstone(s) amongst your aquatic bits and pieces) or try, in
some way, to unblock the stone already in use.
If you decide to have ago at unblocking the airstone, the best method, in my
experience, is to drop it into boiling water to which a few drops of vinegar have been
added. When cool enough to handle the airstone can be lightly brushed (if you brush too
vigorously the airstone may start to disintegrate) with an old toothbrush, which will
dislodge the obstructions. The airstone is then given a good rinse and returned to the
tank.
The 'everlasting' model (which tends to be the most expensive) can be dismantled and
cleaned so that it is able to operate to its maximum potential throughout its life.
Basically it is made of a central tube with two opposing cut out sections. At the lower
end of the tube is a disc shaped end piece. Polo mint shaped rings slide over the tube
from the upper end, the topmost having a simple locking device to keep the rings in
position. The airstone operates by allowing air to escape from the central tube through
the gaps between the faces of each of the rings.
As with the more conventional airstones, the amount of bubbles does tend to diminish
after a while, but this can be easily rectified by dismantling the rings and cleaning
them. This should return the airstone to its original condition. I have however found that
I can extend the length of time between cleanings by cutting a very shallow cross-shaped
groove on the face of each ring. One word of warning - do be very careful whilst cutting
these grooves because these rings are made from a thin plastic material and can so easily
end up shattered into two or more pieces unless the process is carried out very gently.
To make the grooves I use a small hobbyists' hacksaw and can claim that I have not had
to do any maintenance on airstones of this type for the last three years, so it is labour
saving too. Obviously I do 'rub over' the stones when doing the routine maintenance on the
filters, which themselves have also needed no maintenance for three years as well.
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