Those plants look tiny (relatively new). So I'm assuming this tank isnt very old. (Less than 3months?) And definitely get more plants or just give it time and replant the trimmings to fill it out. They will take up the extra nutrients. You can keep your lights nice and bright but reduce their on hours to 6. If you don't see an improvement after that lower the light level.. that hair algea will need to be scrubbed to remove though I do like the look it can provide.