I could only guess about how a sun shade would lower chorine consumption. I expect it would. But it will also reduce the heating of the water. Maybe that doesn't matter so much mid season, but spring and fall you might appreciate getting every bit of heat you can.
I installed my shade sail primarily to give me a place to hide from the sun while in the pool. It gets hot enough here for that to be a thing. I purposely chose a small sale, to give me just enough shade, so that I could maximize the water temp. I solved for chlorine consumption, particularly while away, by installing a salt water chlorine generator, which automates chlorine additions. There are too many advantages and benefits of an SWG to list, but here's one: if you get an SWG, you sure won't miss lugging chlorine jugs from the store to the pool every week!
I take my sail down once a year because I don't need it in off season. I figure that will extend its life. And I bought the best there is, some eight years ago and I cannot see a bit of wear and tear. It wasn't cheap, but worth every penny. It is a structural sail. By that I mean it must be properly tensioned, so you need good, solid attachment points. I can share how I did that if you want to know. But the main thing that accomplishes is it eliminates the sail flopping around annoyingly in the wind. It's more like a roof.
You could install multiple sails, and deploy them as needed. More or less depending on the weather and the sun's position. Multiple shade sails has a very attractive look. I got mine from here:
We Offer the Best Shade Sails on the Market - Shade Sails LLC.
Check out their gallery for lots of ideas. The pics show a lot of heavy-duty support structures, and sure, that's the best way to do it. But I'll show you how I did mine "on the cheap" that works just as well.
