Review on 🔊 EHEIM 100 W Air Pump with Diffuser - Improved SEO-friendly Product Title by Doug Daniels

I don't know the difference between these units as another reviewer mentioned but I got the same unit but more square than round which he one used for a long time. It's pretty quiet, but I don't have anything to compare it to as it's my first pump. The noise level is about the same as my QuietFlow 10 filter. I can hardly hear any additional noise when both are running. I would say it's too strong for my 10 liter tank. I've turned the pump to the lowest setting and tried adjusting the diffuser but it still seems pretty strong. One trick you can try is to tighten the diffuser as tight as possible. I've found that this decreases the size of the bubbles and forces air to exit at all edges. The looser you do this the bigger the bubbles get and it looks like air is only being squeezed out in 2-3 places. My guess is that it takes the path of least resistance, so the tighter you make it, the smaller the retreat path, hence the smaller bubbles. I was about to replace the stone or disc but this seems to have gotten what I wanted. The big bubbles pushed my fish straight up! LAUGH OUT LOUD!