4 foot tank doesn't exactly help us...
Depending on the depth and width, the tank could be bigger or smaller, so we need you to calculate the gallons. I've long since forgotten how to calculate the gallons, though if you're working in liters I can offer that 3.78 liters make one gallon.
As for needing to recycle... have you fixed the filter or are you adding a new one? If it is the former, you might still have to continue it, though hopefully not for too long. If it is the latter, transfer media from the old filter to the new to facilitate bacteria growth, though you will definitely need to give it some more time. -- Rereading your post, simply disregard the "fixing old filter" portion.
Also, if you have the funds and are willing to invest in a new filter, please consider a canister filter instead of just the HOB (hang on back) filters, since they are often adjustable and customizable, and, in general, significantly better filters.
Also, the tank size would help us figure out which type/ size of filter to get.
Good luck