I'm always tweaking things for my sump and just wanted you all know that I swapped out my dirty purigen (was ready for re-charge). I replaced the purigen in my reactor for Two Quart Box - 1 1⁄2” Spheres MarinePure Ceramic Biomedia. Has been running for two weeks now and have observed a big change in my water clarity. I'm sticking with this change for now, it's working perfect for me, I can't tell you if water chemistry has change, I don't test my water, not into what NO2/NO3 are.....