Learn About Aquarium Air Stones

Image of aquarium bubbles
    Air Pumps power air stones

Air stones are used in three or four different applications, and the size, type and shape of your air stone will be dictated by its purpose.

Most new hobbyists think that an air stone is primarily used to add oxygen to your tank. In fact, while there is a small amount of oxygenation taking place where the water contacts the tiny bubbles, most aeration is happening at the agitated surface of the water. The more bubbles that break the surface creating agitation on the surface of the water, the more oxygen is being absorbed into the water.

The main purpose of most air stones is to create circulation through an under gravel filter.

However, the main purpose of most air stones is to create circulation through an under gravel filter. If you are using an under gravel filter driven by an air pump, the air entering the tank will be pushed through a small, compressed, glass bead air stone producing tiny bubbles that rise to the surface inside the filter tube. The rising column of bubbles creates water flow upward that drags filtered water from under the filter plate. Water is dragged down through the gravel, arrives under the filter plate filtered by the gravel, and rises up the tube to the main part of the tank again. By constantly circulating water using the streaming bubbles, the tank is filtered.

    Protein Skimmers
Air stones are used in protein skimmers to push protein scum to the surface of the water for collecting

Protein skimmers use a rising stream of bubbles to push the protein "scum" to the surface of the tank where it can be deposited into a cup for removal. Protein scum appears as a brownish frothy deposit. Unless whipped into a froth, the proteins will not adhere to each other to be collected. In this situation, the finer the bubbles are the more "froth" is induced and the better the scum-collection.

Wooden air stones work best for protein skimmers. They produce tinier bubbles, thus allowing your skimmer to work better.

Decoration, not aeration, is the main purpose of fancy glass bead air stones used to create tank decorations.

Most decorations are run by inexpensive glass bead air stones. The bubbles often need to be larger to push the hinged pieces of the decoration up and down.

Air stones come in long wands as well as small cylinders. These are often dramatic additions to the back wall of a tank, or wrapped around a stone or decoration. Use them at will as long as you understand that decoration, not aeration, is the main purpose.

    Hatching Brine Shrimp

A small glass bead air stone is essential when hatching brine shrimp as the eggs die if not kept constantly turned using turbulence.

    Helping Reduce "dead spots" in Your Tank
Circulation in dead areas of your tank can be aided by an additional air stone in that region.

If you find that one particular area of your tank collects sediment, that indicates poor circulation in that spot. Poor circulation is an indication that your current filter is not producing enough current in some areas of your tank. An additional air stone placed in that location can help disperse the debris and aid in moving the water in that area.

Over time, air stones collect dust, debris, calcium deposits, salt crystals, and algae. They must be periodically replaced or cleaned. (Most can be cleaned at least once)

If your air pump has a good air filter at the intake, the dust problem is probably solved.

Keeping your air stones clean is an important maintenance job.
    All types of air stones can be cleaned in a couple of easy steps.
  1. Remove and rinse the air stones in fresh water while lightly scrubbing accessible build up from the surface.
  2. Allow the stone to dry.
  3. Soak overnight in a solution of bleach water (1/8 cup bleach to 1 cup water).
  4. After soaking, attach the stone to the end of your flexible tubing and pump, then run in a weak solution of vinegar and water for 5 minutes.
  5. Follow by a bubbling, clear water bath for 5 minutes.
  6. Allow to dry, then replace in the tank or store for future use.

If you have particularly hard calcium deposits, use a stronger solution of vinegar or repeat the steps above until the deposits are gone.