I have an Espa Silen 50M SP12 pump and it's a little noisy. I have only just started the pool up but don't recall it making this noise. Don't get me wrong, it's not screaming at me. Also, today I connected my vacuum hose to the pool inlet and heard the pump slow down whilst it tried to remove the air in the hose (I did try and fill the hose up with water beforehand but obviously there was still some in there). It returned to normal speed after about 30 seconds or less. I also noticed that the return flow into the pool with the vacuum hose connected was nowhere near as powerful as without but I'm not sure if this is normal anyway.
Any advice really appreciated.