Step-1   In the Beginning…

Once the new aquarium is set up and first filled with water, it is allowed to run and circulate for a few days. This allows time for any free chlorine to dissipate from the water and any silt or suspended dirt to be caught up by the aquariums filtration units. After this time, when the water clears and temperatures are correct, the turtles are introduced into their new environment. Once this occurs, the turtles begin to deposit their waste products: feces, urine, and uneaten food particles into the surrounding water. These waste products are the initial food source for the bacteria that will ultimately become your biological filter.

Step-2    The Mid Term….

As this food source becomes available, the initial forms of these naturally occurring bacteria begin to process these waste products into various biochemicals. The first bacteria that begins the process are heterotrophic bacteria, these particular aerobic varieties convert much of the proteins and carbohydrates from the turtle’s waste products (through mineralization) into ammonia (NH3). It is this foundation that begins the bacterial food chain that creates the cycling process.

It is also around this time that the aquarium water will normally begin to show a whitish clouding due to the progression of these bacteria and their effect on the water clarity. This is a normal occurrence and shows that the cycling process has begun. Once the cycling is completed, the water will begin to clear.

The next forms of bacteria to join the cycling party are the nitrifiers, or “nitrifying bacteria”, These are bacteria that further the brake down of the turtle’s waste products by converting the now available ammonia into lesser toxic forms. This process is known as oxidation. First of these nitrifiers are the Nitrosomonas bacteria, these forms process the ammonia supplied by the heterotrophic bacteria into nitrite (NO2). Nitrite is still considered a “toxic” element, but lesser so then ammonia. The second are Nitrobacter bacteria, the final stage in the aerobic bacterial succession, these bacteria process the nitrite into nitrate (NO3). Nitrate is generally considered nontoxic in moderate levels and is used by aquatic plants as a nutrient source. Once these three forms of bacteria are firmly established in the aquarium, the system is considered “cycled” and you now have a working biological filter.

Step-3   The End Game:

Now that these various forms of bacteria have established themselves in a working organization, the water will begin to clear, and the bacteria will establish their populations based on the available “food” accessible to them. The more animals expelling waste into the water, the more bacteria can be nurtured. This is the biological “balance” of your aquarium.

Making it Happen

So now that you understand the process of cycling and the importance of establishing a working biological filter system within your aquarium, how exactly do we make it happen? There are a few “tricks of the trade” that can help you quicken the cycling process and create a solid, stable bacterial filter bed. 

First is to recognize that these bacteria (like any animal) have certain requirements to stay living and healthy. All these bacterial forms are “aerobic” bacteria, meaning that they require oxygen to live and to process the turtles waste products. They also require a physical surface for them to “colonize” and live. And of course, the bacteria require a consistent food source, which will be the turtles waste, uneaten food particles, and any dead materials within the water (skin sheds, snails, worms, etc.). As the food source is a given, let’s look at the other two requirements.

To begin, good oxygen levels in the aquarium water are provided primarily by water movement and water turbulation. As the water circulates and surface tensions are broken, gases are exchanged, and oxygen can enter the water. Having your filter “spray” the filtered water back into the aquarium to agitate the water helps to increase the oxygen levels. A separate “bubbler” or air stone with a small aquarium air pump also works well.

Next are the actual surfaces where your bacteria will set up shop. These bacteria will colonize almost any surface within the aquarium that has adequate water movement and available oxygen. Many filtration units will have specifically designed areas within the filter designated for “bio-media” which is simply some material for the bacteria to grow on. Though some filters allow a substantial area for this bio-media, it is seldom enough when dealing with Aquatic Turtles and the rather large amount of waste they produce. To supplement the filter, a one inch layer of medium grade gravel throughout the aquarium bottom provides an excellent bed for bacterial conization and can complement the filters bio-media nicely. This gravel bed should only consist of a size gravel that will allow water to pass easily through it, providing water movement and oxygen to the bacteria. Fine sand is not suitable for this purpose and should be avoided.

Now with a good supply of well oxygenated water, an appropriate area to colonize, and plenty of turtle waste to process, the bacterial cycling of the aquarium should go ahead as designed. Cycling time can vary for each setup, but generally you can count on 14-28 days before the water clarity begins to improve and the aquariums biological filter stabilizes. 

During this beginning start up, it is best not to preform water changes, as adding new water will usually prolong the final stabilization. If you are interested in watching the process in a more in-depth way, you can purchase an aquarium test kit that will show you the individual cycling of the ammonia, nitrites, and nitrates.

Once your aquarium finally cycles, there are normal maintenance procedures that you will perform to keep you biological filter healthy and working; vacuuming the gravel bed to remove any materials that may have settled there, and replacing 25% of the water to dilute nitrates should be performed monthly (along with your regular filter maintenance).