I was running the reactor half-full of Black Diamond carbon by the way. On the positive side for carbon I did see improvement in the look of my green open brain. He has been closed up for about a year and a half. When I bought it was always very fully extended and very fleshy. My nitrates went up to about 40 or so and the brain became very contracted. I thought I would lose it. Nitrates have been near 0 for the last year and a half and the extension never came back fully. I started seeing some extension again over the last few weeks. Maybe due to the carbon. It has swelled up to the point that I need to move that Merulina out of the way. We'll see what happens after the carbon is out for a few weeks. I've added some fish over the last weeks and feeding every day while they are getting acclimated rather than every other day as I normally do so there are a couple of variables at play. May be hard to know for sure.