Review on Seachem PhosGuard 100 mL Bagged - Product Review, Benefits, and Usage Guide by Paul Curd

That saved my aquarium! I had SO bad time with brown algae (diatoms) taking over EVERYTHING. After almost giving up on my planted tank I tried this and everything cleared up. My local water is very high in phosphates. At first I tried following the instructions and removing it after 3-4 days but the algae came back. Now I just leave it in my HOB filter permanently. I have tested my water 1 week after leaving it there and again 2 weeks later and I still have enough phosphate to feed my plants but not the ridiculously high level that my untreated tap water has. Basically it was this or a reverse osmosis system and it's MUCH cheaper!