Russ-IV;1037730 wrote: thought you needed a reactor for matrix to work. similar to denitrate.
I'm not sure - I have it at the bottom of a baffle so water is forced to flow through it. From what I've read, a reactor isn't essential, and it appears to be working for me as my nitrates are near undetectable. I don't even have to clean my glass more than once every 2 weeks.