do you know of anyone with a mature fish tank?? if so ask them for a handful of gravel and put it into your tank or you could even ask your lfs if you could have some of theirs, basically your trying to put some good Bactria into the tank.
im really sorry to go on and i know that your doing the best you can for the fish but a fluvel 1 + is a really small filter so your going to have to do loads of regular water changes.
but dont worry we all started off just like this lol
i started with 4 goldfish in an unfiltered tank because the pet shop told me it was not needed!!