ham07
I love my sea swirls, and would not be without them, great constantly changing flow, and you see nothing in the tank.
They are mounted with two plastic screws that hold them to the back glass. To figure how to connect to an acrylic see sea swirls web site, I believe the info is there, and they are great with answering email questions. I will try to get you pics. My sea swirls are on a closed loop, but they used to be on my return pump, and I feel that was enough flow. My sea swirls run on a Velocity T4 , figuring my head loss I believe they are pumping a combined 1000 gal/hr, and my return pump is pumping 600-700 g/hr for a total flow of 1600-1700 / hr, I think the 1000/hr is enough. ARe two what enough? Two sea swirls? If so yes, but you need a pump that can mximize the flow threw them, 400 gallons each for 800 total, and the overflow should handle it.So figure your head loss and find a pump that willpump 800 g/hr at your head loss and you will have nice flow . If you need more in the future add a closed loop.