Hi Chris, you have it about right. The most important thing is to never let the chlorine get too low or you risk an algae breakout then you have to shock.

Chrissymok, I feel your pain. This is what I would try before doing the whole ascorbic treatment again. Lower the ph to 7.0-7.2, add more sequestering agent proteams metal magic is my choice also. Keep your chlorine at the lower end of the "best guess chart" for a while. The new stains should disappear without the ascorbic acid. If the stains are still there after a day or so, then add a small amount of ascorbic at a time, letting the water circulate between additions until the stain is gone. Add more sequestering agent if you see stains start to appear when your chlorine level is back to normal. Remember high chlorine along with high ph is what makes the metals fall out of solution. As for where your metals are coming from, it is hard to say. If it is from something you added, it should go away with time as your water is replaced.