Hi,
Patrick is correct that I use and produce Foz Down for Phosphate Removal. Thanks Patrick
IME Using Foz Down to bring down excessive Phosphates is the quickest, easiest and most economical method. If your phosphate is >2.5 then your rocks probably have bound up Phosphate as well. As you lower your Phosphate levels the rocks will release it back into the water. I would recommend using Foz Down to eliminate the Phosphate and then you can use your method of choice to keep it low.
If you have any questions I would be glad to answer them.
Cheers,
Tim