This is the only sealer I use.
Caswell EpoxyI prep tanks with Marine Clean (to dissolve petroleum/oil) and Metal Ready (to erode rust deposits) from POR-15. Then dry thoroughly with a heat gun before applying the epoxy.
Most other tank sealers are 'gummy' and for a plastic type sheet. If this sheet starts to separate it will simply pull away from the walls and could completely clog the fuel system. The epoxy is a hard coating. Should a section start to separate, which is already unlikely, the epoxy would crack or chip off. These fragments will sit in the bottom of the tank and shouldn't affect the fueling system. When I use this system, I dump the extra on my shop floor to seal that as well, little by little. I have one patch that has sat for 4 years of driving over, jacks being drug over it, etc and it's still fine.