So anyone care to chime in on this?
Again, the media itself will NOT lower PO4, or anything else for that matter. The bacteria living and multiplying in or on the media will consume ammonia, nitrites,nitrates, phos, carbon etc.. You can then export the bacteria and thereby lower phosphates.
This type of media has been around for decades. But, what we as reef keepers are finding is that if you use 10 X as much media as the manufacturers claim is needed, You will lower your nitrates and phosphates.
This is also the first reef tank that I have ever had that wasn't packed full of " PO4 leaching live rock" So once I found that other people were getting good results with Matrix, I bought a bunch and put it in a canister filter. I hooked it up to my tank for a few weeks ( I also dosed Prodibio Bioclean) then proceeded to remove the live rock from my tank. 6 or so weeks later PO4 was no longer registering on my tests (no color change). I did a test on my tap water and I did see a color change on the test, so I know the solutions are still good.
I am sure I still have PO4 in the tank, but I think it is pretty low. Probably should get better test kits, but don't really want to chase the numbers to zero anyway.:bounce3: