I've never tried a pool cover on my hoop houses but I think you should check out some of the hoophouse plastics at the online greenhouse suppliers. They are engineered specifically for hoophouses and give good performance and durability. I usually buy this type of thing from www.greenhousemegastore.com but there are other suppliers out there.
And its hard to tell from your picture but you might want to install some padding on your hoops. PVC pipes in contact with plastic sheeting produce chlorine gas which eats up the sheeting fairly quickly.
Here's the product I use:
https://www.greenhousemegastor...
Of course if you only have the plastic sheeting on for a few weeks a year it might not be necessary.
Good luck and if you decide to use the pool cover let us know how it works!