Closing pool in Alabama

[swimguy]

I am closing my pool this weekend. It will be my first one since finding TFP. I have two questions regarding the use of shock and algaecide at closing.

1. Can I use the same shock that I use during the spring, summer and fall? It is a 73% Cal Hypo.
2. Is necessary to use a 'winter' algaecide or can I use what I already have at home and use periodically during the summer months. It is a Polyquat 60?

 

[Texas Splash]

1 - Assuming in your vinyl pool your CH is not already too high, you can use Cal-Hypo if you have enough to achieve SLAM level and remain there overnight as noted on the Pool School - Closing an In Ground Pool page. If your water is at or below 60 degrees that shouldn't be a problem. If in doubt about the Cal-Hypo, there's always regular bleach.
2 - Using an algaecide is not mandatory, just preferred by some as "insurance" when the FC level drops. We suggest Polyquat 60, making sure to look for the main ingredient: Poly{oxyethylene(dimethyliminio)Ethylene (dimethyliminio)ethylene dichloride} .

Good luck!