Give the SLAM some time, and you will be fine. There are a few things you can do. Closing the pool in the middle of October and opening the pool at least 30 days before the holiday weekend will make a difference. The other option you have is to cover 80% of the pool with a solid tarp, secure properly, and you can even remove in the winter if you want. This will keep the sun out of the pool as well.
The best thing to do is open the pool up early as your SLAM will go real quick with the cooler temperatures, and once done, your PUMP run time will be at a minimum. I help a few friends close their pools with mesh covers and no matter what if we close mid September, and open about 2 weeks before the holiday, we always have issues with algae. My pool was closed mid September and opened about 30 days ago. Took about 6 hours to clear the pool, but I have a solid tarp, no safety and this makes a huge difference.
The other thing is that you should prepare the pool for closing either by bringing up to SLAM or using Poly 60, not both. You may want to use the Kemtek Poly 60, but will probably require about 1.5 bottles, or $30 and this will get you through the winter. However, the pool must be super clean before doing this. Then you can tell the pool company to not add anything to the pool as it is not needed.
Where were your levels at closing last year?