After reading Jerry's reply to you I apologize for suggesting you ask him for help. Woefully bad advice both to buy a new tank because of a failed o-ring and that you shouldn't clean your tank. I have more thanks than I can count and I wash them thoroughly every time I change a coil or flavor. Been doing this for 6 years. The only negative impact I've experienced from washing is I once rinsed an o-ring down the drain.
Freemax Mesh Pro is one of the best drop in coil tanks I own. I don't know the Fireluke but I would guess same/similar quality, so don't give up on the Freemax line based on bad o-ring or truly horrible advice from Freemax.
Places that rebuild pumps, hydraulics, etc... typically will have o-ring repair kits. Something like this
Loctite 228171 - O-Ring Making Kit, Standard
Basically different diameter long rubber strings that are cut to length and the ends glues together to form and o-ring. The kit itself would cost more than a few tanks but if you found a place like that in town they might help you out. If your university has industrial or engineering courses you might ask those guys to help you out they may have access to some helpful resources.
I have some pretty industrious coworkers in Newfoundland, if you get desperate I can send you a phone number and you can put them to work Newfies love a challenge.
Good luck in your search.