In that tank it’s two gyres. One on each end of the tank that is set on alternating flow.On a more serious note, what kind of settings are you using on your vortech pumps? The flow in that video is pretty impressive. I have 4 MP40s on my 750XXL split 2 on each end and I've been trying to play with placement and settings.
You will see people post saying their chaeto has stopped growing for whatever reason. When you are relying on chaeto for nutrient export where are those nutrients going to go when chaeto isn’t growing?Why do you have this fear?