Apparently the gyres are suppose to be run near the surface under 1-5-2” of water. I run mine about 6-8” below, it creates some awesome undertow and blasts the rock structure. The pair I have is set up so one blows across and the other angled to the surface sits a little higher across. The bottom still has currents but obviously not as strong as mid tank, flower pots, ricordea as well as other Lps on the bottom and constantly getting a current of particulate and broken down matter. They are expensive but worth the money imho...
Parts cost for a new motor block is $60 that’s cheap compared to if you are buying a whole new pump.

If I run my gyre's too close to the surface they suck air. I run them about 4" below the surface. You can always adjust the direction of the flow if you find you are having a problem.

My tank is now wet and I'm testing the gyres.

So far I'd say they are quiet, but not silent.
They make an audible whining sound.

I like the look of them as they are lower profile than powerheads, but if I can't get them silent I may look for other options. The tank is in an open concept area so noise must be kept to a minimum.

Fwiw, I have not played with settings yet.
Just running on the default 50%






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Check how the bushings and props are seated into the housing / cages. Gyres can be finicky and if not assembled correctly can throw a lot of noise. As well, once it slimes up a bit the noise will reduce.