First of all, welcome to the forum! :)
My trainer uses some type of oil-based arena conditioner that works really well in her indoor...she doesn't have to water it any more. It's not too greasy and doesn't affect footing...there is absolutely no dust now. I don't know what type it is, although I can ask her next time I go over there for a lesson.
He knows when you're happy; He knows when you're comfortable; He knows when you're confident; And he always knows when you have carrots.