filtration for a 55 gallon

okay, bio media.
my 20 gallon has 2 of the cartridges with carbon in the penguin 200, + the biowheel.
i really need THAT much more bio media for 1 fish? thats talking 3+x the bio media i have now. well, i guess it makes sense since hes going to get big.
okay, seems whatever combinations i come up with arent working.
so i need the cheapest suggestions youve got for combination canisters with my penguin 200 w/ biowheel. i dont have a lot of money and i want to move him soon.
 
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