OK, here's how I do it and EVERY season I open to clear water. I take into account that the PolyQuat in large amounts causes the FC level to collapse. But I don't do this until the water is AT MOST in the low 60's, colder is better.

1) shock the pool

2) Add 1 quart of polyquat.

3) Wait 24 hours for the chlorine to drop.

4) Shock it up again.

5) Close

Yes, it's really all it takes.