You will probably find it hard to keep your chlorine up - just keep checking and add it as it goes down - get it up to the level for your cya - don't get it to shock, just keep it at a ppm a little higher everyday, keep the ph at 7.2 not higher. As you add the chlorine keep checking to see if the stains come back - if you see a stain start to form, make sure your ph is not higher than 7.2 and add more sequestereing agent, then keep slowly taking the chlorine up.