[pogodzib]

I usually only change mine if I start to notice any algae problems show up in the tank, and I always run less than the recommended amount. I've seen what can happen if phosphate in the water gets pulled out of a system too quickly. It can kill many corals. When first starting to use any ferric oxide material (phosban, etc...), DO NOT USE more than 1/2 of the recommended dosage and gradually use more if you feel the need.