So, if the water surface area of an aquarium is where the main exchange of gases occurs, then why use air stones and have bubbles in an aquarium at all? Because they do have their benefits.
- They are used to drive various types of filters and equipment, such as undergravel filters and some types of protein skimmers.
- Tanks that have solid covers or close fitted hoods on top are prime candidates for stagnant air, low oxygen levels, and high levels of carbon dioxide. However, for these types of set ups that have an undergravel filter powered by an air pump, the fresh air bubbles that come up from the uplift tubes helps to eliminate these problems by provided excellent oxygen and other gas exchange opportunites. A powerhead can be used in place of the air pump and stones to run the undergravel filter, but if the powerhead is not equipped with an aeration feature, or this feature is not used, it can result in low oxygen and low pH.
- Whether using an undergravel filter or not, air bubbles help to move the tank water vertically towards the surface, assisting with oxygen and other gas exchanges.
- They are a cheap way to move the tank water vertically.
- They do create a wall of bubbles that can look pretty cool in an aquarium, not to mention that watching them can be quite soothing.
Ok, so air stones do have some benefits, but are there any down sides to their use? Yes.
- They are not as efficient as powerheads, water pumps, and/or protein skimmers are at creating water movement in an aquarium. All of these are much better at helping with oxygen and other gas exchanges at the water's surface.
- They do not move water fast enough or in adequate volume for what a tank usually needs for good all round, vertical and horizontal, water circulation. This situation can also contribute to a low or insufficient GPH (gallon per hour) tank water turnover time.
- They create a lot of salt spray, that in turn contributes to salt creep problems.
- They clog up.
- They wear out quickly, and usually need replacing often.
- They can give off irregular air flow.
- Air line hoses can get pinched or kinked, which weakens or cuts off the air flow.
- Many times the air pump chosen to run air stones is inadequate, resulting in low air flow pressure.
- Some air flow pressure is lost the longer the distance the air has to travel through the clear tubing from the air pump to the air stones.
- The deeper the tank water, the farther the air has to be pushed downhill to reach the air stones, resulting in loss of air flow pressure.
Learn how to clean and rejuvenate
old clogged air stones for reuse!
If you are using air stones for the sole purpose of aeration in an aquarium, this is may not be enough! For more information and important tips on proper aquarium aeration and water movement, here are some other articles and resources you can refer to.