Hi there Midwest Girl

Welcome to TFP!
One older poster from your area if I recall, would use water filled bleach bottles at to hang from each tie down spot on the pool sized cover. It seemed to work well for him.
Others use tarps and rope and tie it down and pray. Check online pool stores to see what options they sell and perhaps it will give you ideas on what you might buy or perhaps cobble together on your own.
Maddie