Originally Posted by Slade
Cost was the reason I asked, it treats much more water per $$. From what I've read the downside is that you have to be more precise when measuring, and it can't be premixed as a liquid to be stored because it lacks stabilizers.
Even Seachem says it's the same thing in powder form, so I'll give it a shot and see what my firsthand experience is.
My club members use it for large tanks or when they have a lot of tanks. Mine are all under 10g so it seemed impractical for me.
I do plan to buy a gallon of Prime instead of tiny bottles.
Safe is good, just measure carefully.