Sulfur Denitrator

Hi Guys i wanted to see if anyone has had experince with a sulfur denitrator,i purchased an used Korralin denitrator several months back i replaced the sulfur media and set it up as per instructions .
After running for nearly 8 weeks i still cannot get the nirate level fron the effulent ie out of the denitrator to drop at all.
I cannot figure out why this is happening any thoughts?

Im not really sure but i think they take real slow flow rate.. check that for sure..

yes, slow flow rate and it takes a while for the bacteria to grow and for you to start noticing any effects.
I remember David from DT&Inspirations used to build those.