I looked through the skill table for my sci captain today and noticed grav well is listed in the tooltip under particle generators but not listed in the Graviton generators tooltip... so is grav well boosted by both or just 1?
It is boosted by both, differently. Particle Generators boosts the damage it deals, Graviton Generators boosts the strength of its negative Repel and increases its size. (They decided a while back that, since people were complaining about the fact that the change in Repel is negligible, they would reduce the size of the well and let people use Grav Gen to bring it back up to normal. Buffing science skills, yay!)