We just bought a used 28ft x 4ft AGP, set it up and filled it from our well. We've had a small temporary pool up for several years and I have been able to manage the iron problem by adding Iron Myte as I fill the pool each spring and every time I add fresh water. I used 1" trichlor tabs and nothing else in the smaller pool and it worked well.
After filling the big pool, I added Iron Myte according to the label then poured in a gallon of bleach. As expected the water turned colors, then cleared over the next day. However test results 24 hours later were
(as taken with the HTH test kit we got with the pool. My TF-100 has not yet arrived)
Yesterday I put another gallon of bleach in followed 2-16oz bags of dichlor. The water again turned color. This morning test results are
FC >12 (off the scale high)
I backflushed the sand filter and got deep brown muddy looking water out of it, so I backflushed it til it ran clear. Should I just keep running the filter and wait for the water to clear? Does the Iron Myte get 'used up' so I need to add more?