I forgot to add..
If you just add the GAC to a mesh bag and hang it in the sump, it makes it easier to change the media every 3 days. I always have another bag of GAC ready to swap. I let the bio fouled bag dry out for 2 days as its easier to empty out the old GAC that way. Then I rinse off the detritus off the bag in RO and refill if with fresh GAC. HTH someone![]()