I have been a Rowa user and do media change every quarterly to try keep PO4 at zero. Only recently, when my Rowa expanded, I took up Purephos to try, since their price diff is very great. *Cost Savings*
I have no FR so only put the bags of media in a moderate flow aread. PO4 was 0.025 before putting the bag of Purephos to work. Next 3 days, the reading was almost the same but on 4th day, the reading dropped to 0. *though it took more days to reduce the PO4, but it works*
Got to say, though is product maybe have a slower absorption rate, it works. adn on top of that, price is very attractivce. those hesitating should give it a try.
Cheers.