Originally Posted by nat72sherman
I just bought a bag, I was wondering if it matters where u put it in a canister filter. I put it in the very bottom.
From my limited understanding of the product, I don't think it makes much difference where you put it in the canister as long as water flows through it. The only caveat I can see to placement would be to not have it as the first item in the canister. Not knowing whether your canister feed from the top or bottom, I would think you would want some floss or sponge before it so that the bag the Purigen is contained within would not get clogged with detritus. Again, this is only an uneducated opinion, but since it is acting as a chemical filtration stage, I'd like to have it sufficiently after a mechanical filtration stage.