Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
My understanding is that materials that lock up ammonia leave that ammonia in a form that the nitrifying bacteria can still utilize it, and eventually it becomes nitrate, which plants can use.
The web site also says it detoxifies nitrite and nitrate.
Still, this is one of the most commonly used dechlorinators, and I am sure someone would have noticed a nitrogen deficiency in their plants if Prime caused any problems that way.
Another note: I believe these products have a very short life in the tank, perhaps 24-48 hours, so even if it did do something to some of the nitrogen for a day or so, the plants will still have the rest of the week (assuming weekly water changes) to get all the nitrogen they want.