My perspective is that this is making too much of it. It is now mid-April, and here, in North Central NJ it looks like the last freeze is past. I've looked under my mesh cover and the pool looks pretty good. As usual, the water is clear but there's stuff on the bottom.

In the fall, just before closing I put in a quart or two of Polyquat, circulate the water for 48 hours more, then raise the FC to 15ppm and close. I try to do this at the end of September/early October (I have solar heating) when the water goes down to the low 60's.

My plan is
1.this weekend to remove the cover,
2.hook up the pump/filter and plumbing.
3.half the solar panels (I need some replacements for the other half), and get them working.
4.test my water
5.Add what it needs--first pH adjust and chlorine.
6.When the water reaches 60, toss in the Dolphin 3 or 4 times
7. Set up the new solar reel, and attach the cover to it and cover the pool to hold in heat.