Not at all sure what your "this" refers to -- water color, filter build-up, ?
Regardless, get your pH up. A reading of 6.6 probably means 6.6 or LESS, not 6.6! Low pH damages all types of pools. If you want to get a handle on what's in your pool water, a metal bucket test (see sticking in metal section) will allow you to rule metal contamination in, or out.
"Metal Klear" is mystery goo -- SeaKlear has carefully obscured data in the MSDS sheet, to the point that it's almost useless as a safety document -- so I have no idea what effect it has had on your pool water.
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