dougall, not trying to pick a fight, but if the tank is healthy what could be released back into the tank? Nitrates is my best guess from gunked up media...but that can happen, if unlikely, in other tanks. Regular water changes "should" fix that...shouldn't they? You know I'm a lame tester...
Yeah, this whole "what can be released that wasn't there before?" aspect of this always had me thinking...I mean, if things THAT toxic were already in the water, then something is wrong with the maintenance schedule...Basically anything the carbon might have adsorbed.
If there were nothing, there would be no reason for it in the first place, so I am assuming it may release something, toxic or otherwise.
Honestly I would expect nothing bad. But there is potential. It should be slow enough to not be noticable as long as regular water changes take place.. water changes won't make any difference to whatever is in the carbon unless it is changed too.. in which case don't replace it.
Or just ditch the whole thing and feed less for a couple of days in case of a mini cycle.
Seriously, though, if I'm doing weekly changes of about 50-percent and we only have two fancy goldfish in a 60 gallon, should I be alright with removing the carts from time to time and blasting them under strong tap water?