Hairline Crack in Poured Foundation Wall
1st, what's the problem w/the hairline crack ??? if its a static crk, i'd leave it alone,,, if its moving or leaking water, different story,,, w/o inspection or more inf, have no idea if hydraulic's the answer, either.
'drylock' isn't if there's water intrusion so that's out ALTHO, if dry, it might be suitable,,, you need to determine if hydrophyllic OR hydrophobic mtl should be installed - epoxy is generally for either conc crk welding, bonding, or coating.