<a href=showthread.php?s=&postid=12869174#post12869174 target=_blank>Originally posted</a> by bigclops
i thought phosphate media never leaches.. it just stops working.. so basically you test before you run it.. to see where you are at.. then run the media.. usually last for a few months.. once you start getting readings of phosphate you know that it is time to change the media