Are you using Jebao WaveMaker? If so I have 2 of the gyres in a master/slave configuration and I believe mine are in a constant mode because the algernate cycling on and off. It's been a long time since I've done anything with the settings but if I remember correctly wave cycles on and off at the set intensity, and else is a random flow.
I have mine set to wave 1 which is the pulse on and off. It makes a gentle wave in my tank and has eliminated a few dead spots along the back of the tank which I had when I was running it in else mode.