I've used charcoal and Purigen.
Purigen is what I use everyday for my 36g. The only downside I've noticed is that after "recharging" it a half-dozen times, it needs to be recharged more often. It does last and definitely makes a difference.
I only use activated carbon after dosing the tank with medicine, or if the water offends my nose. I don't run it every day. Maybe once every other month or so?
That's my tank before the move...
🐟 Diana Lee 🐠
😎 the Redhead 😎