Posted: Thu Jan 17, 2008 12:43 am
When the tank or filter or filter media is new, the bio filter doesn't function yet because the bacteria haven't grown, so ammonia (turtle waste) builds up to a high level rapidly. Then, the population of ammonia consuming bacteria explodes, or "blooms" in the water. At this point, if you test the water you find that ammonia is high and the other chemicals (nitrite and nitrate) are still low.
Then, the newly grown ammonia processing bacteria consume the ammonia and the ammonia level goes down. The byproduct of ammonia processing is nitrite. Therefore, as the ammonia level is declining, the nitrite level goes up. In the presence of nitrite, another set of bacteria, the nitrite consuming bacteria, explodes, or "blooms" so the water stays cloudy.
Then, the newly grown nitrite consuming bacteria consume the nitrite and the nitrite level goes down. The byproduct of nitrite processing is nitrate.
Finally, the water is clear because there aren't excesses of ammonia and nitrite in the water to feed the bacterial blooms. Colonies of the nitrifying bacteria are established on surfaces like in your bio filter and they keep the ammonia and nitrite levels unmeasureably low.
Nitrate continues to build until the water is changed. Since nitrate is fertalizer for plants, including algae, if it is allowed to build too high, algae will bloom.
You can track this really interesting process day by day with a water testing kit and observe the ammonia going up, then down as nitrite rises, then the nitrite also goes down as nitrate rises. The whole cycle takes a week or two.
SpotsMama