Originally Posted by
saltn00b
http:///forum/post/2764996
how old are the LR? did you buy them from a LFS or from another reefer?
phosphates get locked up in the LR and dont come out. Once these giant "sponges" are filled with PO4 and can no longer absorb it, the water column starts to build up PO4 content. if it is all very old LR then maybe you want to carefully (cure) switch out your LR.
you can also replace or add LS / aragonite that will perform the same function.
My tank is only 8 months old so the rock is pretty new and i have about 2 inches of LS on top of the playsand
I am going to get a better phos. test kit this weekend the api are hard to read.