Does this look like a stain from metals?

[smallpooldad]

Unfortunately at that high a CyA my experience has been, no idea why, that Ascorbic Acid Method does not work very well at CyA evels over 70.

Assuming you are now refilling the pool the following would apply:

After you have added the Ascorbic Acid and the sequesterant run the pump 24/7 for 2 days.

After that:

Ideally you should drain a second time assuming that the stain gets removed, if not then do not drain (why because you removed nothing). This helps stop the metal from settling out, although it is true DE filters do a better job of catching particles, but eventually they will find there way back into the pool.

Wash out the DE regardless of if you do, or do not drain (but again only wash if the stain was removed), otherwise the metal will return to the pool.

I hope the above is clear enough.

Aloha