Review on KEDSUM Quiet Rechargeable Battery-Operated Aquarium Air Pump With Dual Outlets - Perfect For Fish Tank, Outdoor Fishing, Transport, And Emergencies by Gregory Braddock

I bought 2 of these one for each aquarium in my bedroom. One of the units is very quiet and just what I wanted. However the other unit is very loud in comparison, so loud that I have to turn it off at night when I am trying to sleep. I sent it back and requested a new one thinking maybe I just got a bad unit. However, the replacement unit I received is even a little bit louder than the unit I sent back. I'm not sure what the deal is but I would love to have 2 quiet units so I can keep them both running while I am sleeping.