Air Stones for Aquariums
Why Get an Air stone for Your Aquarium, Are Air Stones Necessary?
(The First Tank Guide)
Are Air Stones Necessary for a Fish Tank?
Whether or not air stones are necessary really depends on what you mean by necessary, and will vary from one system to another.
If you have an aquarium filter that is run by an air pump, an air stone will be beneficial. An air stone will create an abundant cascade of small to tiny bubbles rather than a limited number of larger bubbles. These smaller bubbles will be much more effective at moving water through the filter, making the filter more effective and efficient.
How Do Air Stones Increase the Oxygen in the Aquarium Water?
As for increasing the oxygenation of the water, the best thing air stones do is provide good water circulation - so if your filter is adequate to the tank, it will already be providing adequate water circulation, and the benefit from an air stone and air pump will be minimal and unnecessary.
The air stone will increase the water circulation more than an undiffused air feed into the tank from an air pump, and the bubbles themselves will also increase the surface area of the water more, but the real benefit from an air stone as far as oxygenation goes is just the increase in circulation.
What Kind of Air Stone Should I Get?
There are actually two different questions here. One concern is for the make-up of the air stone, and the other is with the shape or size of the air stone.
So, first, the type of air stone... In situations where I have had need or desire to use an air stone, I have found that the compressed glass bead air stones tend to be the best - with one exception - If you are using an air stone driven protein skimmer on your marine aquarium, the wooden air stones give off a finer cascade of bubbles and therefore make the skimmer much more efficient.
The shape of the air stone is also of concern. For most filters and most 'action ornaments' that can take an air stone, the 1" (2.5cm) long, 1/2" (1.25cm) diameter air stones will work best. But you will want to look at the instructions for the filter or decoration to see if they specify a different shape of air stone.
If the air stone is purely for decoration, then the shape is really up to you and your tastes. There are long air stones in varying lengths, round ones in several sizes, square ones, rectangular ones, and a wide variety of other shapes and sizes - even ones that can be bent and shaped to what you want. When you're looking for an air stone to use purely for decoration in your fish tank, there are many choices. Just remember that these larger air stones will also require a larger air pump.
Of course, with any kind of air stone, you need to remember that any air stone will need to be replaced every few months as they get clogged with dust, bacteria, and algae.