Just added gyre 130 to my DT. Running it in alternating gyre mode , 30% (forward), 40% (reverse). If I run it at 40% (forward) is starts moving the 1" sand bed around. I left a MP10 opposite running at Reef Crest Random (low %) - figure I leave MP10 for flow for when I clean (book says needed every 3 months) the gyre 130 and in case gyre fails I have some flow. I can only hear the MP10, the gyre is silent at 40%. It has constant mode, pulse mode, alternating gyre mode, and feed mode - pretty easy to select on controller. Some of the corals closest to it I have up on a frag rack are getting a lot of flow - had to move some as they were getting rattled around. So far I like it. Glad I bought it.
I've had the 130 for about a week. I ran it one day in stock config and it was perfectly quiet. One I installed the part B for reverse flow, it makes noise now, in reverse. I installed it correctly, took it apart again and installed it per directions a second time and it still makes noise in reverse. Not sure why. I do love the flow though. I have Bare bottom so running it at max.