[Hamburg Mattenfilter any good?]

My Mattenfilter works primo.I put a picture frame around my tank and planted the foam with javamoss and ferns.the older the better it works.you can always put it in as a corner filter.all my tanks got one.very cheap just the foam ,i bought a whole sheat 2m*1,2m for a 100 bucks last me a lifetime and does a lot of tanks biggest one 640 litres.

[What Filter]

Check out the "Hamburger Mattenfilter" just put it into google search can't remember the websites.very popular in germany and yankee land befor all the hightech crab came in. It a 5cm porous filterfoam(little bit hard to get here in Kiwiland) It works like magic never have to clean it.And you can plant it so it blends in.Worth looking at it.

[Any ideas for alternatives/DIY for Ceramic Noodles]

Just use scoria/lava rocks.give em a good scrub,so.they are really porous

[Spray Bar Position]

If you got a lot of plants in your tank I would fit the spraybar under the watersurface so not to disturb it and loose CO2.

[Pressurised CO2]

What about Soda-Stream bottles.Every garagesale or fleamarket has them for a few bucks.The problem is to get the gas to release slowly.need needle valve.