The problem is that the RBTA will wander alot when new and may float around a while. When you add him, stop the pumps for an hour or so. Run one at 30% for a day. Slowly up the flow as you get confident he is happy and not moving. FWIW, my rose got sucked into my 6000 and it survived, but I would avoid it if possible, it looked scalped, no tentacles on one side. It is still alive so they are tough once established, that was over a year ago.