You could only use too much if you were to pack it so full and tight that the water would not pass through.. But it would be more of a waste to do that..since it should be re-energized often.
For best results you want about 1/2 lb of carbon for every 50gallons of aquarium water.. Or 1Tbs of carbon per gallon of water..
sorry.. didnt feel like starting a new thread....
Is it necesary to use carbon?..... i mean czn i run the tank with out carbon i recently took it out of mt canister and runing the canister with out it!
i think carbon helps in making the water crystal clear but isnt a must to use it
and i have a phosebane reactor that i use for corbon and i use only @ 5-7 tbs maybe less depending on how i feel but the most is 7 . works great for keeping yellow cast down.
Carbon also removes toxins from the water, such as those produced by leathers and some softies. IMO, and my opinion only, a reef tank should run activated carbon. I replace mine about once a month or so. I have a Fluval FX5 on my 125g tank.
It does help, but yeah, you only need it if you want to or if you have anything in there that can produce toxins, such as anemones, cucumbers, things like that.