Denitrifier coil

I read the thread and was really amazed what it can do. I have decided to "try" to make one. Can anyone here has made one give me some dos and don'ts?

And is it true that once it working, I don't have to worry about water change and just dose whatever is needed because of the low nitrate?

Thanks!
GKW

http://www.3reef.com/forums/new-hobby/natural-nitrate-removal-31746.html?highlight=denitrifier