purchased to replace a large external filtering device that was complicated to dismantle for cleaning, for an aquarium of over 100 liters. I thought for a long time for this type of device, one end is simple and effective, positioned in the aquarium, near the surface, little noisy. it will just wash foams quite regularly, following the instructions (alternating, one rinse foam) every 15 days, I use it for several months now and no problem, I take off a star because the suction cups easily slip a little but it allows me to adjust the height of the device relative to the level of water that can vary.
