I have an Eheim 2215 and am using it for FW Cichlid tank, You do not have to use the noodle pad that came with it, mine is packed as follows:
1st Layer (bottom) = 2" Enfimech (Eheim ceramic rings)
2nd Layer = Coarse blue pad
3rd Layer = 3" Substrat Pro (Eheim high surface area biological glass balls)
4th Layer = 1 - 2 " of mechanical filter material (filter floss/pad)
5th Layer = 20 oz Chemi-pure (Any carbon or your choice)
6th Layer (last/top) = Same as 4th Layer.
SW applications are a little different.
You can re-use the blue coarse pad many times after a good cleaning, however you must replace the dense white pad because it is difficult to clean. What you can do is get some filter pad material and use the either pad as a template and make new ones they work just as good and wont cost you a fortune.
Note: On the bottom of the canister put one green plastic grid feet down then add your filter media and on the very top put the other green plastic grid feet up followed by the power head. I put the Substrat Pro in a media bag because it makes it easier to clean the filter. The Ceramic rings on the bottom should not be put in a media bag because their job is to trap large particles and assist in the biological filtration.
Tip: I use a little vaseline to lubricate the large O-Ring that goes around the power head every time I clean the filter. Hopefully yours came with the quick disconnects, if so make sure the top valve is open when you attempt to reinstall the powerhead ( it will slide right on), if they are both closed it will be nearly impossible to reinstall the powerhead(Also when attempting to open the canister make sure the top valve is open otherwise it is nearly impossible to open (Vacuum)). Whenever you clean the filter do not use straight tap water on any of the biological filtration media as this will destroy any/all beneficial bacteria the media is housing and don't allow the media to dry out either. To clean the biological media you just need to rinse it out using the water from your fish tank. Don't forget to de-chlorinate your tap water before putting it in the tank.
I hope this helps you out.