Hi @corey ; so I am monitoring and keeping flow through vertex media reactors regulated so Aston not bottom out no3. Seems to be getting lower now after not much change for couple months. I have increased flow a bit since last week when no3 was down to 5 ppm . Now it’s a bit lower(2 per Red Sea kit — light pink on test vial) I am adjusting thruput to try to prevent bottom out scenario. Po3 tested today (Hanna) .03) so hope to keep these parameters for now if I can . I have a fuge section in sump that has mostly hairy green type algea also so that may be a factor in my numbers. I also have been utilizing purple non sulpher bacteria recently to try to get more “ good” bacteria into play. I am sorry for the run on but I hope to get more solid info to forward soon. Thanks JimIm at the same like 2-3ppm via salifert. Brought from 150ppm to 2.5ppm no3. I actually have to read it from the side which is pink. From the top it looks clearish.