How quickly do you all expect to see results? I added 1 lt of siporax to my 40B over week ago and haven't seen even the slightest tick downward using a salifert NO3 test. Two days ago I added a second liter. I'm hoping that 2 liters of siporax will provide some reduction, right? BTW, my tank has been hovering around 7 ppm for over a year. What would be a realistic expectation of 2L of siporax in a 40B?