Hello,
I have the 3k in my 240 running at 100% and it was dead quiet for about 7 months. Then it started making a slight hmm noise. I cleaned it in vinegar etc sparkling clean and still had the noise. What actually makes the noise go away is not cleaning it actually. But there are four plastic bushings, when they wear out it makes the noise and it’s basicslly saying to change them out. It took me like five minutes to swap them out and it comes with an extra set. If you email them they will send another set out but their customer service is super friendly. They don’t really know their own product so don’t be disheartened when you actually know more about your gyre than they do. Also helpful hint none of them are consistent with the noise. Some are always silent some right off the get go, some like mine 7 months. Luck of the draw. But I can say my tank is 240 and it’s on the back wall. It definitely moves water but nothing that’s knocking corals off the rocks, unless it’s not glued down and not placed well. However it would be a mistake to place any corals super close to it. Not because it will knock them over but it will tear the flesh right off sps and lps really quick. I use alternate modes on mine for more random dead spot flow. Hopefully you get one with the newer controller, if yours doesn’t come with lcd controller make sure you call them. There is a huge difference and for example even my lfs who just had some come in came with the old black controller. So just a heads up but you should like it and I’d clean it when you see things growing on it. Mine sometimes takes forever, and for example I just cleaned it two months ago and it looks worse than when I cleaned it the first time in 7 months. But mine is still quiet after I swapped the bushings out. Also careful with the magnet on smaller tanks it is literally strong enough to break the glass if you let it slam against it when you install it and or clean etc. larger tanks like mine not so much but I still don’t suggest it. They are crazy strong.