Lanthanum chloride and gfo

[Proteus]

I had a po4 spike a couple weeks ago which was caused from a bag of hydroton I put in sump when it was first setup and I forgot about it.. I have since taken out and used foz down to control phosphates.. I also changed my gfo.

Question is. Will the lanthanum chloride bond to gfo if the gfo is holding phosphates rendering the gfo useless?

Currently the po4 level is 0.04 and will rise to 0.06 after 24hrs