Hi Roger, I have a Peninsula tank 168mm long by 750mm depth and 570mm wide with Fluval SP4 return pump entering the tank at the opposite end to the weir....the tank is LPS dominated and currently uses a Vortech MP40 and MP60 on the weir end either side. IF I were to replace them with the new Stream 3 how many would you suggest and what sort of placement given the only options are either end of the tank (back glass is up against a wall)? Thanks, Andy