I don't think you need to start out as low as 500.....but if you must, I think you'd need more steps in between to really clear them up. Try 500, 800, 1000, 1500, 2000...?
Lately, I've been hand wet sanding all mine...starting with 800, then 1000, next 1200, then 1500 and finally using a 3M 3000...