If you can, I'd fit it in the
sump. Mine have leaked from time to time (always my fault), and I feel better knowing they're on the wet side of the glass
I think they reccomend no less than 130 grams so there is enough matterial for the bed to fluidize propperly. I went straight in using a full can of Phosban and didn't have any trouble. I like that I don't have to change it that often.
Just make sure you rinse it. I know the instructions tell you to rinse it too, but do it REALLY well.
