So i found out yesterday after filling my truck up that the top has rusted through and i have a hole in my tank. I picked up another tank in good condition from a junk yard for $30 but was wondering if there is something i can spray on the new tank to help keep it from rusting in the future

 

Bed liner would work. But 1st I'd clean, sand it really well, apply a recommended primer for the bed liner, rockerguard, under coating or whatever you choose to use. Just follow the directions