Mustard algae - first time infection

[handy1]

Thanks all. I have no idea how the metals got in there, but we had the pool redone about 2 years ago, and perhaps the decking folks dropped something in when they stained.

I assume the advice is to shock - with chlorine shock, but without stabilizer- household bleach, right? And the measurement is free chlorine (FC)?

Thanks for all your help! (Yes I have a test kit to use).