Here's a pretty good thread on denitrators on our local forum (NJReefers.org)
http://www.njreefers.org/joomla/inde...&topic=4537.15
It's a 4 page thread but the link above starts on page 2 where it gets good. I'm Carlo there not Cayars.
I even talked about making one from Coralife Calcium Reactors which are available in 250 and 500 models for well less money then any typical nitrate reactor you will buy commercially. Technique applies to just about any calcium reactor. I like recirc designs myself however.
Give it a read and post any question you have here and I'd be more then happy to help. Or start a new thread and PM me the address.
Carlo