:smot: :slfg:
I have been advised by another person who I trust that carbon doesn't dump the toxins back in, it just stops adsorbing, so the point being made is not necessarily wrong even if you don't agreed with the approach of the poster.
To answer Caryl:
I didn't add any silicone, it was just rubber with a slit cut in it, squashed around the divider and jammed in the tank.