Hi Meesh.
I am not a fan of Metal Free because I've been involved with a number of threads where it doesn't/hasn't effectively sequestered the metal...its citirc acid, not the HEDP (phosphonic acid) that we normally recommend for metal sequestering. My hunch is that, given the citric acid, this product's mgfs believe it will reicipate metal for carryout...which is a controversial kettle o snakes and IME, partly hogwash
The two brands we like for sequestering ar Metal Magic by proteam or Jacks Magic, each available online at
Pool Chemicals, Hot Tub Chemicals and Supplies | Pool Geek , which is located in Michigan so would be a fast ship for you. The need for sequestrant and subsequent wear off is dependent on metal load. 1 ppm copper is very high.
In your shoes, I'd do a 50% water change now to get BOTH your cya and copper levels down by half, THEN sequester the copper. You will use less chlorine and less sequestrant for what we have left of the season.
Some people report the belief that CUlator works but I personally did not find it effective for cost, but am on well and have a constant source of metal. Your mileage may vary. The company is good about supporting folks who use it and giving tips, so it may indeed help in this case. Again, it will be of more benefit at a much lower copper level than what you have.
As for Nature2...at TFP we typically recommend discontinuing its use due to metal load and generally avoid the use of pucks because they constantly increase your cya, which makes the critical [fc/cya][/FC/cya] target difficult to mantain.
Sometimes, though in northern climes, the cya will zero out over the winter (especially if you don't open early) in which case some people can get away with using stabilized products and keeping an eye on FC. Eg. I used to use pucks for 2 or 3 weeks in October while letting the pool cool down for closure and at the same time deliberately increasing my cya a bit before winter...but by increasing, I mean from 30 to 50. I'm now SWG, so my cold-weather strategy will be liquid chlorine
But generally, its easiest to keep your cya at a constant and dose with liquid chlorine daily to the FC:cya targets.
Since you do have a heater and can get back up to temp reasonably quickly, my vote is for at least a partial drain to ease the management required for the rest of the season.
Hope that helps give you some things to consider.