Just recently started using benereef and impressed with the results. Can't speak to PO4 reduction but the feeding response for all my LPS and other stuff like gonis is pretty impressive. Really boosted a bunch of hammers and torches I recently got including some today that look like they have been in my tank for weeks. Granted I have not used it by itself yet except one broadcast feed. I spot feed a mix of it, paracoccus powder, and aminos. I was adding a bit of reefroids but pretty much done with it. I actually got the idea of benereef from reading something where topshelf says they feed Euphyllia a mix of it and reefroids. I suspect they have much lower nutrient tanks than I run and can get away with the reefrods.