Too powerful for my needs (400L tank) so I use it on the lowest setting. Higher setting makes more noise as well. The air stones are reasonable but I changed them for the ones with smaller bubbles.
The pump is noisy but it sits inside the tank cabinet, so it isn’t a problem. The noisiest parts now are the air stones actually (I haven’t found silent ones yet). Less powerful pump (200) might be a better option overall in my case.
Most of the time you cannot hear it, as it vibrates it will move a bit and then you get slight humming. Just replace it and quiet again. Plenty of air, adjustable. Great product I have had in a long time.
Best pump on the market for the price. GO FOR IT!!!!
Had one of these pumps lasted several years. Never needed cleaning and very silent as it says on the box.
Makes a great replacement for the original Bi Orb pump and certainly provides more than enough air to overcome the constrictive nature of the Bi Orb neck design.