Aqua sobriquet
Member
My Biomaster 350 isn’t the quietest external I’ve ever had, that honour goes to a Tetratec EX400. It wasn’t too bad when I first installed it though. After a couple of months it did become noisy, with the usual “impeller hum”. I fitted a small piece of soft plastic (from a container that was going into recycling) between the impeller support and Oase’s “silencer” modification applied to later models. It’s been like this for quite a few months but it’s only just occurred to me today during routine maintenance that it may be of interest to others. The white plastic offcut (arrowed) is about 1.1mm thick.
