well they are both water conditioners But Fritz-gard Does Not remover ammonia, nitries or nitrates. If you were looking for a water conditioner then either would be fine. If you are trying to lower your ammonia, nitrate or nitrite levels then use Amquel. Thats why I asked what were you using it for. IMO Prime does work better for lowering the levels better than Amquel , just like Rbishop said.