If the plugin area was black/burnt, it was most likely not the pump, rather it was either the gfic or a combination of salt and moisture that caused a short at the outlet. I would venture to say that if you tested for continuity past the plug and got reasonable resistance readings, that you'll only need to replace the plug. Lots of folks have problems with outlets near the tank that are not protected from spray and salt from either the sump or the overflow or the skimmer, etc. Areas that have air and water mixed end up sending out a fine suspended mist of saltwater. The droplets land on items nearby, dry and leave the salt as a residue on the cord/plug, etc. After about a month of this occurring, there can be enough salt residue to conduct an electrical current, which may be experienced as a mild tingle when unplugging the item affected, ot touching an item grounded through such a plug. Multiple outlet service bars are quite prone to this, especially if they are mounted in the same cabinet that the sump is located in. If you have any open source of spray (and it may appear to be insignificant, like the return chamber for the return lines from the tank, or the skimmer air vents), either locate the electricals in a separate watertight cabinet or a sealed section of the sump cabinet, or place the electricals in another location altogether. Check your electrical supply bars for corrosion, and clean and inspect your electricals and cords once a month at least.
OK, I will stop now before you guys start calling me "DAD"...
