Flatworm Exit?

[noirsphynx]

Has anyone ever used flatworm exit without a canister filter? The only filtration I have is a sump but it says that you must use activated carbon in a canister filter. I don't want to go out and drop a bunch of money on a filter to only use it once. I've removed all my fish & coral from the tank so the only things left in there are my live rock, 4 large nassarius snails & 3 turbos. Do you think rigging up some carbon in cheesecloth to my flow would work just as well?