Water Clarity - Need Education

I'm posting this in the metals/stains forum because I have metals in my pool and have them under 'Metal Control'. I want to make sure that the information I get is relevant to a pool with Metals.

I've gotten my pool clear but I'm having trouble determining if it is Crystal Clear. There is a very suttle dull distortion to the water keeping me from saying that it is crystal clear. Can it be crystal clear? Or is the dull distortion something I'm going to have to live with because of the 'Metal Control'.

Numbers:

FC 2.5
CC .5 (the 10ml solution turned the slightes shade of red, and 1 drop made it completely clear)
TC 3
PH 7.2
ALK 90 - 100
CYA - about 10 (is there a way to measure below 20?)

Q. What does things like Polysheen/Blue stuff do? Is it reccomended? Will it mess up my water balance?

I find that the less added to the water the better. Everything has some effect on something else. When dealing with metals, it can take a while to get your water crystal clear. Once you get the water clear and balanced, it will stay crystal clear - it does take POP. I find running the pool at low ph will help the water clear more quickly. Using a skimmer sock, and keeping up with chlorine so that it never gets below the "best guess chart", will maintain the water in a crystal clear way. I have used floc on occasion to clear a really cloudy pool. I don't like clarifiers, because if you ever let clarifier dry it is like a plastic - yuck!. My own experience is the less the better.