I run a fish only system now. My tank is 4' x 3' x 16" with one overflow on the back wall. I currently have one gyre xf150 on the overflow blowing towards the front of the tank. I have a second XF150 inbound. My ultimate goal is to keep detritus suspended off the barebottom and have it enter the overflow. The little x marks in the tank are rockwork which could be rearranged if needed.
My question is what would the best placement for two gyres? Would vertical be better for swirling action? Anyone have experience with arranging two of them to strategically keep the most detritus from settling?