Just got some the other day all I can say is wow.this stuff is great the algae is just melting away. I had too much po4 bound up in my rocks that was leaching into the water column.i was over feeding. I have been vodka dosing since dec.2013. I still feed a lot but not much algae since running sea gel and dosing vodka.the sea gel has cut the algaes source of food phosphorous and silicates.my Rodi filter has since been replaced