Maxspect Gyre 350 noise?

[WunderWagen]

I have two Maxspect Gyre XF350's in each corner vertically mounted in my Red Sea XL525. They have been running for a few months now, and I have a strange noise issue with them. I have cleaned them and still have the same issue. They sound very quiet up to 60% (which is my current setting), but they get noticeably louder (buzzing sound) when set to 70% or higher. I would have expected a progressively louder buzz as you increase output... but this is a pretty dramatic change from just 60% to 70%. Has anyone else experienced this with the Gyres?

 

[Rocks reef]

That is normal with most powerheads/wavemakers. The faster they rotate, the more 'noise' you will hear.

 

[WunderWagen]

True, and I have heard the noise many times related to rotation... but what seems to be happening is a very big change just from 60% to 70%... quiet at 60%, then you can hear it in the next room at 70%. I cleaned the units, and it did not change the noise. Very strange... I had XF330 Gyres before and do not remember them acting this way.