I just replaced my above ground 12X20 pool liner and just completely filled my pool with tap water. I live in the the North East.

I want to properly get my pool water balanced. The question is, I am planning on using Metal Free (to deactivate metals) and then shocking it. I was told to use the Metal Free first in order to avoid turning the water brown? Is this true. Do I need to do this. Any recommendations.
Can anyone help me with this initial step. Your help was greatly appreciated in the past. TIA