brightwell makes a export no-3, emily uses all the bright well lil cubes on her tank and they work well. ive used the export phosphate on my tank and also works well. Louis had some last i saw, also dont forget to buy microbactor to seed them as you need to soak them for 24 hours with tank water and microbactor. i just ran them in a media bag. in a low flow area in sump.

http://brightwellaquatics.com/products/xport_no3.php