Bought one on black friday this year, already had to toss out some dense chaeto twice, so it appears to be working fine for me. I haven't had to dose any of the extra nitrate or iron yet either. Hoping I don't run into any of these issues you guys seem to be seeing, but for now, I love this thing, it's keeping my phosphates right around 0.04 ppm according to my Hanna ULR.