Positioning of second filter

[Myrtle]

I know this has been covered in various ways already, but I still have a few questions. My tank is 4' long and at present there is just the fluval 405 running but I have an eheim 2026 to add tomorrow 🙂 . The inlet/outlet pipes of the fluval are both in the back right corner with the diffuser in front of the outlet. Would I be better off putting the other filter in the back right corner too, or in the back left corner. If I put it in the back left corner, I'd have to put the second diffuser at the left hand side. Any opinions on which would be the better position?

 

[aaronnorth]

are you getting enough flow/ circulation at the left side? If not then add the filter there to improve things