Here's a picture of my newest DIY project.
This is probably the easiest project I have done and was very cheap.
Total in parts is about $17.
Water comes in the bottom, goes through a mesh and through the media, through a mesh again and out the top.
It holds about 1 cup of media so it measures out very nicely.
the 1 1/2" pvc is just there to hold the 2 meshes in place.

Nice project.

interesting, got a pic of the finished product ??

I haven't taken any pics of it yet, I'll try to take some tonight.
It is working extremely well though, I have two of these (one with carbon, one with phosphate sponge) connected to a MJ900 and inline ball valves to control the flow.