Juwel Filter advice - Add Cirax or Sponge to upper basket

[NATO]

I'm wanting to make sure I get the utmost filtration from the internal Juwel filter in my Rio 125 tank.

At the moment the upper and lower filter baskets are populated as per Juwel's instructions;

White Poly
Carbon
Nitrax Green
Coarse Blue
----
Cirax
Fine Blue
Fine Blue

I was thinking of removing the carbon sponge in the upper basket and putting a Cirax at the bottom of it, but is Cirax the best choice?

White Poly
Nitrax Green
Coarse Blue
<Add Cirax here>?
----
Cirax
Fine Blue
Fine Blue

I know Cirax provides a large surface area for bacteria to grow, but given the upper basket is a higher flow area, is it a good choice or would I be better off with a coarse or fine sponge?

Thanks in advance for all advice!

 

[NATO]

I tinkered with the filter a little, I now have the following setup:

(Top to bottom)
White Poly
Nitrax Green
Coarse Blue
Citrax
---------------
Citrax
Citrax
Fine Blue

Does this look like a good setup to maximise the surface area for beneficial bacteria?

 

[Fidgetromeo]

I have mine set up as:

White pad
Carbon sponge
Green sponge
2x course blue sponge
----------------
3x Fine blue sponge