On the carbon being different. I think the pellet type is less effective than the granular type. The pellet type have been treat, powdered, then formed into pellets.
That is what I read anyways.
For the OP I would say change out the old filters and be sure you have negative pressure in the room.
That is what I read anyways.
For the OP I would say change out the old filters and be sure you have negative pressure in the room.