fish farming
The COLDEP process resolves the main technical limitations encountered by water recirculation systems in aquariums:

  • Decrease in the oxygenation level of the water.
  • CO accumulationdissolved in water.
  • Risk of nitrogen supersaturation.
  • Abundance of small particles <30 µm which are not captured by conventional filters, which clog drum filters and reduce the effectiveness of UV treatments.
  • Presence of bacteria and viruses in the water.
  • Presence of microalgae.
  • Energy cost of the solutions implemented to solve these problems.
particulate extraction - water clarification - biosecurity

Aquarium water clarification and treatment

The microbubbles created in the system trap impurities as they rise and create a scum at the top of the column. This scum which is sucked up by the vacuum carries with it the particles which are trapped inside. These extracted particles are between 0.3 and 30 µm and are not trapped in conventional systems.

Minimum size of the particles extracted

Minimum achievable turbidity


Optical transmittance of rejected water


Reduction of bacterial load

less viral load

Electricity consumption per m³ of treated water

Particle extraction by the COLDEP system also makes it possible to trap bacteria, viruses and parasites in the water, thus ensuring the biosecurity of the installation. The clarification of the water also makes it possible to guarantee optimum UV efficiency and the absence of microalgae.

There is the possibility of extracting continuously or only a few hours a day.

dissolved gas management

Regulation of O concentration2 and N2

The bubbles associated with the vacuum created at the top of the column make it possible to achieve unmatched aeration and degassing efficiency. In addition, the COLDEP process makes it possible to prevent any risk of nitrogen supersaturation.


Minimum oxygen saturation level

Electricity consumption per m³ of treated water

Chart showing the limited nitrogen saturation in the water of a system with VAL comparing to a system with no VAL
The opinion of professionals


The COLDEP device was installed in a tropical basin of 200 m3, in which we had problems with water turbidity, despite conventional filtration, and the start of the growth of filamentous algae linked to an increase in the nitrate level. About a month after commissioning, the effects were very visible for these two problems. We have found excellent transparency in the water and the algae have completely disappeared.

Dominique barthelemy

Curator in charge of the living environment, President of the Union des Conservateurs d'Aquariums (UCA), OCEANOPOLIS BREST

we did it

Our references