The present invention comprises an efficient filtration process of water from a tank, where the filtration is performed over a small volume of water and not on the totality of the water from the tank； the process comprises the following steps: (a) emitting ultrasonic waves in the tank； (b) adding a flocculant agent to the water； (c) covering the tank bottom with a suctioning device which suctions a water flow with flocculated particles, discharging to a collecting effluent line； (d) filtering the effluent flow of the suctioning device from said collecting effluent line； and (e) returning the filtered flow to the tank. The present invention additionally comprises a suctioning device used in said efficient filtration process.
