Just because a plant doesnt smell much in flowering doesnt mean it has a low thc content.northern lights is a low odour strain and it will get u rightly stoned!
Different strains have different smells thats just the way it is, How long did u flush it for before harvesting? maybe the left over ferts gave it a bad taste!
Or maybe its shit weed? it could be any number of things really
Hope that helps!
CWL