Fwiw. I've been using biogen by aquavitro. I had some nitrates I couldnt keep under 10ppm. I religously did water changes as well weekly. Lightened feedings and had some macros in refug. Now about 6 months later I can' t get a trace of nitrates and I feed heavier. I have some coloration problems which seem to be related to my lighting and/or. Reef fuel feedings. I'm ready to yank the pellets as my chaeto grows beastly. I really think they worked for me but, had I changed my refug bulb months back, i may never had needed to run them. I'm pulling the reactor today since the batch has dwindled and chaeto is doing its job very well. Phosphates are 0 too. I'd say avoid them but if I didnt have room for macros , i'd give em a run. Good luck.