It will go away when you get organics down. As said above, get rid of Cannister and just use it for a few (2 or 3 max) days at a time to polish water or run carbon in it for a week at a time, again if you run carbon too long it becomes ineffective and turn into a nitrate factory. Quit useing miricle cures, find the problem and things will take care of themselves.Most Carbon and phosphate reactors are good, buy good carbon, some are trash. When you start medicateing (De-Nitrate and all the other miracle cures) and don't address the problem, ie fish load, over feeding, bad flow, dead spots and non RO or contaminated saltwater for water changes, you make the LFS happy. By the way thats a good way to judge a LFS, do they ask questions and suggest problem areas, or just tell you to do water changes and sell you chemicals.