Anything that roots itself in the substrate will appreciate root tabs, and I've never heard of anybody "overdosing" with root tabs. One every 3 inches or so, in a grid through the tank, will do just fine. Making your own with Osmocote Plus and either freezing some into tiny ice cubes and inserting them, or ordering some empty capsules online (<$5 shipped) to stick in there, is the cheapest bet, though I've had good success with RootMedic tabs.
And my icon is Hamish, from Braveheart. He was clearly the hero of the movie, with the crazy Irish guy running a close second.