Circulation pump
Creates water circulation inside the aquarium. Fundamental in marine aquariums for the health of corals and in all aquariums to distribute oxygen and nutrients.
Detailed explanation
Water circulation is one of the most underestimated aspects in aquarium hobby. Without adequate flow, dead zones form where debris accumulates, oxygen is scarce, and anaerobic bacteria produce hydrogen sulfide.
In marine aquariums, circulation pumps are essential. SPS corals require strong, turbulent flow that simulates wave action on the reef. Soft and LPS corals prefer moderate, indirect flow. The total flow rate of the pumps should be at least 20-40 times the volume of the aquarium per hour.
The controllable pumps (such as Tunze, EcoTech Vortech, Jebao) allow you to vary the intensity and create different flow patterns during the day. Some simulate tides with alternating flows.
In tropical freshwater aquariums, circulation serves to distribute CO2 to the plants and maintain a uniform temperature. River fish (like Corydoras) appreciate a moderate current. Slow-water fish (like Bettas) suffer with too much current.
In ponds, circulation pumps are mainly used to avoid thermal stratification in summer and to oxygenate the water in depth. In winter they are reduced so as not to disturb hibernating fish.
In brackish aquariums, circulation must be sufficient to maintain uniform salinity throughout the aquarium.
How it is measured
The flow rate is measured in litres per hour (l/h). The ratio between the total flow rate of the pumps and the volume of the aquarium is calculated. In marine aquariums, aim for 20-40x. In freshwater aquariums 5-10x are sufficient.
Coralia Lab monitors this parameter with AI diagnostics. Tank Score alerts you when a value moves outside the recommended range for your aquarium.
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