What are you attempting to do with it?
If you are lowering phosphates from a high level, I would warn that this stuff lowers it really fast sometimes and it can shock your tank. I would use 1/4-1/2 the amount recommended and test to make sure it doesn’t drop too fast. It is really easy to zero out phosphates with Phosguard or GFO in my experience. Which is not typically a good thing unless you have a fish only system.