I am not sure about the product you mention, however one known approach to
reducing algae is to get higher plants growing vigorously. Basically make sure
the higher plants have everything they need to thrive, and they will eat up the
phosphates for you.

My bet is that getting your plants to grow vigorously will work better and more
cheaply than some chemical designed to take up phosphates that you must
continually add.

-Bruce Geist