I have not personally used it, but that's what no-mor advertises as the 2.5lb equivilent. At $2.99, that a great deal, but it is just dry acid (PH down) so it does add sulfur to the water over time. At that price, having some on hand when you run out of MA is not a bad idea, but I'd stick with MA for long term use as you avoide the sulfur issue.