BTW robert, I'm not the one having the problem with profile. I'm using flourite now. This is Methods thread. It just seems you thought I started this thread. lol.
Never say impossible. I know without a doubt profile was the problem in increasing my phosphates, and KH too! Yeah it doesn't contain phosphate in itself, but if you do some research, fuller earth is a type of ceramic, VERY similar to phosphate removing filter media.
I have a thread all about the problem called "where did all this PO4 come from?" if you care to follow up on it. But basically it practically removed all the PO4 that was added by the tap. Even after very little dosing all of it was removed to 0. After just a week suddenly the phosphates where 2.4ppm and then never lowered. It apparently became saturated with phosphate and then became a time releasing fertilizer - very similar to old activated carbon. Then after that my KH unexplainably went past 30 degrees. All I had was some plants and profile...what else is too blame?