I vote Bristlenose too
Though mine tends to prefer brown algae to green. The brown is usually easier for them to suck off than the green, or at least, that's why I've observed.
It never hurts to pull out an algae pad and scrub down the tank once a week; that'll keep algae growth down.
Algae feeds off of light and nitrates, so if your Severum is creating a lot of waste, you may be getting high nitrates, which can be removed with water changes. Also, make sure the tank isn't in any direct sunlight. That may help with some of your algae too