Coral box QP5 very noisy

[Bars]

I have had 2 of these for the past couple of months and one of them has been very noisy for quite a while. Gave them a good vinegar dip to clear off all the junk yesterday and the noise seems to be even worse.

I don't mind a bit of noise, but I can hear it in the other room. Even a bit of a rattle would've been fine by me, but I can't stand the high pitched/whistle noise. Any ideas what it could be? Nothing looks broken at least...

E: forgot to mention. I'm using the 'nature' setting (randomized flowrate) for both of them. When it starts ramping up the noise gets very loud. At the lowest flowrate I can't hear the noise.

 

[dank reefer]

Did you take them apart and clean the shaft and all? I run 2 Coral box pumps in my daughters tank, and the only time I hear them is when they need a good cleaning.

 

[Bars]

I did, cleaned everything I could.

Just gave it a good press and that seems to have solved it. Probably just didn't put it back together correctly.