Filtration
The water in an aquarium with turtles is more heavily polluted compared to the water in an aquarium with fish. Aquatic turtles are often messy eaters and produce more urine and feces. Food leftovers, urine and faeces are a food source for bacteria, including pathogenic bacteria. It is therefore important for the health of turtles and other aquarium inhabitants that food residues and faeces are kept to a minimum and are quickly removed from the aquarium.
To keep the water of our animals as clean as possible, the following matters are important:
- Don't feed too much. Too much food makes the animals fat and also produces more faeces
Remove uneaten food. - Provide an appropriate sized enclosure for the animals. A larger water volume stays clean for longer.
- Invest in a good filter of sufficient capacity. A good filter removes debris from the water and provides a place for nitrifying bacteria to settle and work their magic.
- Make sure the water contains sufficient oxygen. Nitrifying bacteria can do their useful work better in water with a lot of oxygen. This can be done, for example, by using an air pump with an airstone. Another, simpler method, is to hang the outlet of the filter high above the water level and let the water fall into the tank. This also brings more oxygen into the water.
- If possible, add aquatic plants to the water. They absorb nitrates from the water. Duckweed and waterweed are very suitable for this purpose.
- Change the water regularly. Unless you use a denitrifying filter, nitrate will not be broken down further and will accumulate in the water.
- Sand as a bottom substrate is more suitable than gravel. Dirt can settle in between the gravel, accumulates there and starts to rot. Dirt remains on the surface of sand and is broken into small pieces by the turtles swimming around and is thus more easily sucked into the filter.
Nitrogen Cycle
The nitrogen cycle is a biological process in which nitrogenous organic material is converted into nitrate by bacteria. The cycle starts with the food and excrement of our animals. These organic materials contain proteins and amino acids.
Ammonia (NH3) is a substance that is released during the breakdown of these proteins and amino acids. Dissolved in water, it occurs in two forms, ammonium (NH4) and ammonia (NH3). The ratio between these two substances depends on the pH (acidity), temperature and salinity of the water. Ammonia is an irritant and poisonous to many aquatic animals, such as fish, even in small amounts. Aquatic turtles tolerate higher concentrations of ammonia in the water than fish, but for their well-being it should not be present in their water in measurable quantities.
In an oxygen-rich environment, Nitrosomas bacteria convert ammonia into nitrite (NO2). Nitrite is also a toxic substance. This substance displaces oxygen on the hemoglobin of red blood cells, causing the organism to lack oxygen (organisms that breathe in water). This substance must not be present in measurably quantities.
The last step in the nitrogen cycle is the conversion of nitrite into nitrate (NO3) Nitrobacter bacteria. Nitrate is much less toxic than the ammonia and nitrite. Nitrate cannot be further broken down by bacteria in an oxygen-rich environment. Nitrate can be removed from the water by performing a water change. Fast-growing water are also very useful to remove nitrate from the water.