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What Every Aquarist Needs to Know

David's avatar


Wednesday, October 10, 2007


There are some things that seems obvious to me that may not be obvious to the general public. I will try to hit on these basic points in this entry.

Every aquatic habitat needs three types of filtration in order to support aquatic life: Mechanical, Biological and Chemical. Mechanical filtration removes any debris floating in the water. Biological filtration removes the waste products produced by the animals. Chemical filtration removes any chemicals in the water that may harm the animals.

First, let us discuss biological filtration. Fish produce ammonia. Ammonia is a metabolic waste product analogous to urine in humans. Ammonia is toxic. Those of you who have used it for cleaning around the house are well aware of this little fact. It is excreted from a fish’s gills, into the surrounding water where, in the wild, it is quickly rinsed away by the currents. In a protected environment, ammonia has to be eliminated differently, which is by biological filtration. In a well aged aquarium, a culture of nitrifying bacteria will have had enough time to colonize and grow. Nitrifying bacteria quickly converts the ammonia to nitrate, which is much less toxic than ammonia. Nitrate can be removed in three ways.

  1. We can dilute nitrate by removing old water and replacing it with clean water. This is called a water change and it is recommended to be done at least once every week. For some heavily stocked exhibits at the Aquarium, this is done daily.
  2. We can remove it naturally with photosynthesizers. Some exhibits, such as Shark Lagoon, have live macroalgae or plants because they naturally consume nitrogenous wastes such as nitrate.
  3. We can remove it by using chemicals. This is usually the last resort.

Remember I said that nitrifying bacteria is abundant in well aged aquariums? The process of aging or breaking in a new aquarium is called “cycling”. It can take a while and is why new aquariums cannot support a lot of animals. The process of cycling can be accelerated by adding things to aquariums that already have a culture of nitrifying bacteria growing on them. Live rock, rocks obtained from the ocean, will already be well colonized by bactera; after all, there is no body of water more well aged than the ocean. There are also chemicals available in most pet shops that stimulate bacterial growth in water. Still, there is nothing more effective in cyling any aquarium like time and patience.

It is always a good idea to provide a place for the nitrifying bacteria to grow, which is why many exhibits also have sand filters and bioball towers. Both apparatuses work the same way and that is, they both have media inside that has a lot of surface area for bacteria to grow on. Water from the aquarium is pumped through them so that the bacteria can come in contact with the ammonia in the water and degrade the ammonia.

Next, let us discuss mechanical filtration. This can be achieved by running water through a material that will allow water to pass through but not free-floating debris. One commonly used apparatus for doing this is the filter bag. It is simply a bag made of cloth that allows water to flow through but catches everything else. Filter floss is a material kind of like a giant cottonball can catch debris in the water.

Chemical filtration is quite complex because there are many kinds of chemical filtration. I will talk about two kinds of equipment and the kind of chemical filtration they provide.

Everybody has blown bubbles in milk using a straw at some point in their life. But have you ever stopped to think, why is it that the bubbles you blow in milk last much longer than the bubbles you blow in water? Milk has a lot of organic chemicals in it and most organic chemicals will link together with chemicals similar to it. By blowing bubbles into the milk, you are letting the organic chemicals in the milk to link up, wrap around the air and produce a bubble. Fractionators, also known as protein skimmers, work the same way. A fractionator is a giant bubble machine that constantly blows bubbles into the water so that the organic chemicals can form bubbles. But because the fractionator blows so many bubbles, the bubbles will overflow and carry with them the previously dissolved organic chemicals in the water. Fractionators clean the water by removing organic chemicals.

Anything that the fractionator leaves behind can be picked up with the ozonizer. The ozonizer is a machine that zaps air and produces ozone. Ozone is a highly reactive chemical that readily reacts with anything. The ozone that the ozonizer produces is run though the water so that it can react with and degrade chemicals in the water that may potentially harm the animals. The byproduct of the ozone is then absorbed by activated charcoal. Activated charcoal has a lot of microscopic pores that the ozone byproducts can attach to. By keeping a fresh supply of activated charcoal in the water and having ozone pumped into the water, we can keep the water crystal clear.

That was a lot of information but do not worry about knowing it all. For all you aquarium hobbyists and wannabe hobbyists out there, just remember two things: regardless what kind of fish or system you have, you must perform water changes.

Even though it sounds like a good idea, do not add too many fish into a system at once. Have patience!

What Every Aquarist Needs to Know
This device adjusts the amount of ozone added to the Amber Forest exhibit's system.  | ©David Chen
What Every Aquarist Needs to Know
This fractionator is taller than me but i'm not a short guy, I'm 6'0". There are even larger fractionators at the Aquarium but I had trouble getting to them.  | ©David Chen
What Every Aquarist Needs to Know
The bioball tower is to the left. It is full of blue balls that provide a lot of surface area for bacteria to grow on. Down below is the sump. The sump serves as a receptacle for water that is waiting to be pumped back into the aquarium. This typical setup is found plumbed into the round ray touch pool.  | ©David Chen

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Anitza's avatar


Thursday, October 11, 2007 01:25 PM

I love the look on people’s faces when I explain what the protein skimmer does and how it mimics what the ocean does itself. When it dawns on them that the sea foam that once looked to romantic on a sunset stroll with their loved one is actually a magnet for all the waste in the ocean, well, let’s just say they’ll watch out for dirty foam from now on! Love the pics David!

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