After 24 hours and if the stain is gone, you can start to balance the water. Your ph and alkalinity will be probably be low after the ascorbic acid, and you will probably have trouble keeping chlorine in the water. You can get your ph up to 7.2 and then start to add the bleach, add enough to take it up about 2ppms, waiting a little while and adding more until you reach about 4 or 5 for your cya. If you start to see stain forming, make sure your ph is no higher than 7.2 and add more metal free. You should be fine. Just don't shock for at least a week, maybe 2. You can keep your chlorine at the high side for your cya which at 50 would be 6-8ppms, but I wouldn't go higher for the 2 weeks. Feel free to ask any questions you have, good luck