I mentioned about a month or two back in a similar thread that the Seachem reps told me that using it to control trates or trites in an established system causes the issue to convert to a neutral or inert phase for about 3 days and then it changes back. The idea is that you can add it to bind your levels at safe point until you can do more water changes, your skimmer might remove the waste in that time, or possibly your bio filter can process the waste into a more permanent solution. But after 3 days if it has not been converted or removed it will be released back into it's normal form.

A word of caution was mentioned during the discussion. If your tank had a die off, is over fed etc.., then you could be in trouble at the 3-4 day mark. Basically if your levels are high and you add some Amquel or Prime to control them, don't do any water changes, keep over feeding (or let the dead fish continue to rot), what will happen is that your levels will continue to climb back up and then when the original bound solution is released, you'll end up with your levels being double what they were days before.