IMO, everyone is correct ...up to a point. AC can remove some of the metals we dose, but it's minimal. I think Purigen is a better option as it will remove the nitrogenous organics more efficiently than AC and those are the only organics we are really concerned about (neither AC or Purigen will remove the organic phosphorus). AC works, but it will be useless after about a week or two (sooner with a lot of organics). So, if you use AC, make sure to put new AC in weekly and be sure to select high-quality AC, as increasing amounts of phosphates are often leeched from carbon as quality decreases. Purigen will last longer and does not unload organics once filled and, as mentioned, can be recharged. Like AC, Purigen can remove some traces, but it is my understanding that such activity is far less than AC.
We should also mention that neither of these chemical filters remove nitrates or ammonia. They remove the organics that ultimately can become those products.
Last edited by Deanna; 09-12-2019 at 11:08 PM.