Sounds good apart from the carbon. Carbon is generally a waste of time unless you are removing medication from the water or something.
It stops working within a few days and (though I dont know if this is true) can appaerently start to leach stuf out back into the water again.
At best, it's completly not needed on a regular tank.
Would be far better using the space for more biomax, or whatever other bio media takes your fancy.
Agree. Carbon's primary function is as a chemical filtration media and aquarists generally leave it on the shelf until needed to remove medicatons, tannins (yellowing from bogwood) or the occasional organic smell of unknown origin. Its quite good for these purposes but as ThreeFingers says, it "adsorbs" for 3 days and then is ready to be removed and tossed in the trash.
BUT, that doesn't mean that carbon won't serve as a biological or mechanical media (the other two functions of a filter), it will, its just not optimal for them. As a mechanical it will indeed trap some debris because its a gravel-like layer and things will get trapped as the water passes through. And, more importantly, it can serve as the surface area for the 2 species of beneficial bacteria we want and will be ok at this. The main reason its not optimal is that it gradually crumbles, eventually into dust sized particals and gets taken out with water changes. So, compared to ceramic rings or ceramic pebbles, both of which last virtually forever, its not nearly as good. Sponge doesn't last as long as ceramics but is also a much better biomedia than carbon.
But anyway, since you've already been through a lot and probably don't want to get into that filter again, just thought I'd throw this out to say it won't be such a bad thing I don't think. At some later time you should begin transitioning it to a better biomedia, just not all at once.
Also, its generally a myth that carbon leaches the chemicals its "adsorbed" back out. It will simply equalize, so in extreme cases that can technically happen but as a practical matter it hardly ever does this. This was discussed in a thread in the science section by bignose.
~~waterdrop~~
