at the reviews I expected something better. Despite construction according to instructions, the power to be desired leaves much. Already after 2 weeks small amounts of bubbles came only at the top of the Ausströmsteinchens (even if I omit the return valve). I lift the stone further up come back for more, but performance should be enough for a 40cm deep AQ ... I wonder how in other customer even a pond can be aerated so -.- Since the pump is also quite noisy, I put them on polystyrene to dampen the vibration.
