No it is not standard practice and if the carbon is older than 15 to 20 days it is no longer "activated" and is performing as biological filtration (and to a lesser extent as mechanical filtration).daisycutter said:never thought of that i thought it was just standard practice to use it ill put some foam in the small filter instead
I also used activated carbon for a brief period until I found the following concerning HITH disease while researching the literature:
(I have published this link before but it has been several months since doing so).
Also please note that after approximately 7 days biological digestion bacteria begins growing in typical mechanical media (ie. foam).
I therefore "change out" my mechanical media at a frequency of less than 7 days.