"ChemTek" or "KemTek"? There are many "ChemTek" companies.

No pool chemical I know of is LABELED as HEDP; many contain HEDP; the few listed, and even fewer linked to Amazon are ones I could identify as CONTAINING HEDP, and nothing else. And, it doesn't look like the "Kem-Tek Metal and Calcium Eliminator" calls itself a "clarifier". Look at what you've got, and then look at this photo:



I'm guessing, you've gotten the wrong thing.

Citric acid is a less effective and cheaper product than ascorbic acid. Like ascorbic acid it is COMPLETELY incompatible with chlorine. Unlike ascorbic acid, some nasty by-products form when you began re-chlorinating citric acid.

Also, you need to put on your thinking had a minute. You say
I have been using SeaKlear Clarifier for the past two years . . . The SeaKlear also says that it removes metals from the pool.
But, if it were actually true that SeaKlear "removed" metals . . . you wouldn't be having a green hair problem!