Does this look like a stain from metals?

[ScottsdaleSwim]

Ohmygosh. That was so confusing.

I used a brown Vitamin C tablet so that's probably where the charcoal stain came from. I put a trichlor puck on it the other day and the stains didn't fade at all so lets assume it's metal.

The pool heater is shot..and disconnected..probably just prior to the sale of the house. I'm betting that's where the metal came from.

Okay. So- I'm draining the pool because the CYA is out of control.

This is where I start after refilling.
CYA to 50.
chlorine to 0
Ph to 6.0-7.0 but not higher
sprinkle approx 3lbs of ascorbic acid around pool and on stains
add 2 quarts of algeacide 60 (because I'm worried about algae bloom)
immediately add 6 quarts of metal out (is this what they call a sequestrant?

And this is where my confusion really begins
"In regards to a sand filter adding DE helped catch more particles, then again this may be more in the mind than in reality. With a 300 lb sand filter (9,000 gal pool) add enough DE, through the skimmer box, to raise the pressure by 1, this is about 3 cups, add one cup at a time and wait 15 to 20 minutes. Once you have started the ascorbic acid process you may notice, if you have a sand or small filter, the pressure rising dramatically and your filter slowing down. I back washed for 1 minute only after each of the first two 12 hour periods as the filter became blocked.

It is best to first backwash and then COMPLETELY DRAIN the pool after having run the pump for 48 hours non-stop. If you do not drain the metal will eventually fall out of solution and cause the stains to reappear via deposit.

I have to drain the pool twice? I have a DE filter so the sand filter part doesn't apply to me.
Can someone help me by picking up the process after the sequestrant??

I'm supposed to drain first to get my levels down right, and then drain again after the ascorbic acid treatment??
Should I treat for metals and then drain it even though my CYA is over 300? Chlorine is still at about 15.

I swear I read it more than twice. I'm just not understanding ...
thanks for your help.